The Basic Concept of LastErrorText

There are a few important things about the LastErrorText:

1) Each Chilkat method call (or property access) clears the LastErrorText and writes new information about what transpired during the method call.  This information is available regardless of the success/failure of the method call.  Most Chilkat objects include a VerboseLogging property that controls whether more or less information is recorded.  Only use VerboseLogging for debugging situations as it may impact performance.  (Note: Some property accesses will not write anything to LastErrorText because the internal implementation is trivial and it could adversely affect performance, especially if the property is used in a “for” loop statement.)

2) Make sure to get the LastErrorText from the same object instance.  If interested in the LastErrorText after calling imap.FetchSingle, then get imap.LastErrorText.  (Not email.LastErrorText, or any other object instance.)

3) LastErrorText contains information about the last method call for an object instance.  (i.e. the most recently called method or property)  To get the information about what occurred during a call to imap.FetchSingle (for example), one must get the contents of the LastErrorText *before* calling any other method or property on the object.  (Thus the significance of the word “Last” in “LastErrorText”.)

4) The LastErrorText indicates the name of the method (or property) for which it contains information.  For example:

DllDate: Jan 19 2012
UnlockPrefix: NONE
Username: joe
Architecture: Little Endian; 32-bit
Language: ActiveX

LastErrorText Standard Information

All Chilkat classes / components use a property named LastErrorText.  It provides a way to get detailed information about what happened during any Chilkat method call.  The LastErrorText will contain information even when the method call is successful.

In almost every case, the LastErrorText will begin with information such as this:

    DllDate: Jun  2 2009
    UnlockPrefix: ****
    Username: Jake
    Component: ActiveX

When contacting Chilkat support ( you will probably be asked to provide the contents of the LastErrorText property. The information at the beginning of the LastErrorText is important. Here are the details:

DllDate: It tells Chilkat support how old of a version of the Chilkat component/library is being used. In most cases, if the DllDate is old, you will be asked to try the latest released version. The reason is that most problem reports are already fixed in the latest version (especially if the DllDate is old) and the information in LastErrorText is always improving. It’s best to begin investigating a problem by using the latest version.

Also, Chilkat may provide a new build and ask the customer to re-test. In a surprisingly large percentage of cases (especially when using the ActiveX or .NET components), the customer does not actually use the new build and re-test using the same old-version. The DllDate allows Chilkat support to know if the customer is really testing with the new build.

UnlockPrefix: Provides Chilkat support with licensing information. If your 1-year support expired, you *may* be given a 1-support grace incident with the expectation that support will be renewed prior to any future support requests.

Username: This is the logged-on Windows OS username of the process. The main reason it is included is to allow us know if the process is an IIS worker process, or perhaps running as a Windows Service. In these cases, file access and I/O permissions may be more restricted than when running other applications.

Component: Allows Chilkat support to know if you are using the ActiveX, .NET, VC++ libs (and the version of VC++), etc. It saves time from having to ask which Chilkat lib/component is being used.

Also.. the first line after the opening “ChilkatLog” will be the name of the method call. In the sample above, it can be seen that “Connect” was the method call. (Quite often, a customer will not capture the contents immediately after the intended method call. )

VB6 Runtime error 91 – Object variable or With block variable not set

A Chilkat method that returns an object must be checked for NULL ( also known as Nothing, nil, nada, etc. in other programming languages).  A NULL return value indicates failure.  In this case, check the contents of the object instance’s LastErrorText property.

In Visual Basic 6.0, this is the error message you’d get when trying to dereference a NULL object reference:

VB Runtime Error 91

Here is an example of checking for a NULL return value in VB6:

Set xml = xml0.HttpGet("")
If (xml Is Nothing) Then
    Text1.Text = xml0.LastErrorText
    Exit Sub
End If

Username in LastErrorText


I discovered that the program is trying to use the Computer System Username to instead of the username given in the program code to connect to the server.


The Chilkat component is not trying to use the Computer System username.

The LastErrorText will (almost) always include the process’s logged-on username in the beginning, along with other pieces of information such as DllDate, component type (.NET, ActiveX, C++, …) , etc.    The reason we log the username is to make it easy for us to know whether your application code is running within the context of IIS or a Windows Service, where special considerations might apply.   It helps Chilkat provide support more efficiently.

  DllDate: 20 Jul 2009
  Unlockprefix: XXXXXXFTP
  Username XXXXXX
  Component: .Net 2.0


The first step in debugging a Chilkat method that returns a failed status is to examine the contents of the LastErrorText property. The LastErrorText property will contain information about the last method call on the object.

For example:

success = mailman.SendEmail(email);
textBox1.Text = mailman.LastErrorText;

The LastErrorText property is standard on all Chilkat classes/objects.  The error information may also
be accessed in XML or HTML format via the LastErrorXml and LastErrorHtml properties.
It may also be saved to a file by calling SaveLastError.

The LastErrorText will contain information about what transpired within a method call
even when the method succeeds.  Therefore, if a method returns a value indicating success,
but something did not go as expected, examine the contents of LastErrorText.

Note: The purpose of the LastErrorText is to help programmers determine the cause of a problem. It contains detailed information and is not something you would normally display to non-technical end-users.

It is designed to provide most (if not all) of the information that should be sent to when requesting support.  Please be sure to cut-and-paste the contents of the LastErrorText into your support email request.  (Please: Simply cut-and-paste the text.  This is much preferable to screen captures, MS-Word docs, or image files (JPG, GIF,  BMP) etc.)

When examining the LastErrorText, look for the “DllDate” that is contained within it.
If it is more than a few months old, Chilkat will most likely ask you to try the latest
pre-release from   This is to ensure that you
are not reporting a problem that is already fixed, and it also makes sure the LastErrorText
has the best information.  The contents of LastErrorText is continually being improved
and refined.

C++ Notes:

The LastErrorText “property” is actually accessed as one of two methods:
void LastErrorText(CkString &str),
const char *lastErrorText(void)