INFO: How to Diagnose and Resolve Some Automation Errors


This article describes how to diagnose and resolve some automation errors. The information in this article may be useful if you receive 429 and 438 error messages when you are automating an ActiveX/COM server from Visual Basic.

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Error 429

Error 429 typically occurs when code tries to instantiate an object. This error can be caused in many ways. The following list includes some of the most common scenarios that could cause this error:

  • License information for a particular component is not present.
  • A component is missing or is not registered.
  • A DCOM issue exists.
  • A Packaging and Deployment Wizard (PDW) issue exists.

License Information for a Particular Component Is Not Present

When you try to site a control from the Visual Basic toolbox onto a form, the code may throw the following 429 error:

License Information For This Component Not Found. You Do Not Have An Appropriate License To Use This Functionality In The Design Environment.
This error occurs when the problem computer does not have the appropriate design-time license for the control that is being added. For additional information about how to resolve this problem, click the article number below to view the article in the Microsoft Knowledge Base:

194751 FILE: VB6Cli.exe Fixes License Problems with Visual Basic 6.0

A Component Is Missing or Is Not Registered

When you try to run a Visual Basic program after you distribute it, the program throws the following run-time error 429:

ActiveX component can't create object.

The run-time error 429 usually occurs if you do not include one or more of the components that your program requires or uses. One common example is the File System object that is described in the following Microsoft Knowledge Base article:

247979 PRB: Error 429 Using MSDN File System Object Programming Example
The run-time error 429 can also occur if you do not distribute the correct Visual Basic runtime files that are needed by your program executable (.exe) file. Make certain that you are distributing the correct runtime files by creating a Setup package for your program by using the Package and Deployment Wizard (PDW).

Another way that the run-time error 429 occurs is when one of the components that is needed by the program is not registered correctly. The best way to troubleshoot what line of code is causing this error is to add tracing code. The recommended method is to write to a file (or the event log) instead of generating message boxes. After you determine which line of code is throwing this error, make certain that the problem component is registered. For example, you narrow down the error to the following line of code:

Dim fs as Scripting.FileSystemObject
Set fs = New Scripting.FileSystemObject ' this line throws error 429
The File System object is contained in the Scrrun.dll file. Make certain that this DLL file is installed on the target computer, and that it is correctly registered.

A DCOM Issue Exists

The attempt to access a DCOM server from a remote-client program throws a runtime error 429.
For additional information about how to troubleshoot this issue, click the article numbers below to view the articles in the Microsoft Knowledge Base:

177394 HOWTO: Troubleshoot Run-Time Error '429' in DCOM Applications
183607 HOWTO: Configure DCOM for Visual Basic Using DCOMCNFG.EXE

A Packaging and Deployment Wizard (PDW) Issue Exists

You can get this error when you are trying to use the PDW, either by trying to start the wizard, or by clicking the Package or Deploy button. For additional information about how to troubleshoot this issue with the PDW, click the article number below to view the article in the Microsoft Knowledge Base:

255726 PRB: Error 429 Occurs When You Use the Package and Deployment Wizard

Run Time Error 438 - Object Doesn't Support this Property or Method

The most common cause of error 438 is not maintaining binary compatibility between successive versions of your components. Each COM interface has an associated GUID that is called an interface ID (IID). Each coclass has an associated GUID that is called class ID (CLSID). When you compile an ActiveX component in Visual Basic, the CLSIDs and IIDs are compiled into the component's type library.


A program that consists of a Visual Basic client and an ActiveX DLL is released to the user community. At a later time, additional functionality is to be added to the DLL component. The necessary modifications are made, and the ActiveX DLL is compiled without maintaining binary compatibility. When the DLL is released, the client that is trying to use the DLL will throw run time error 438. The reason this occurs is that when the DLL was compiled, a fresh set of GUIDs was compiled into the DLL, and the client has no reference to these new GUIDs. This is why it is important to maintain binary compatibility with the last-released version of the component when you are trying to release a newer version.

Another example for the runtime error 438 would be including the wrong version of Microsoft Data Access Components (MDAC) in the distribution package. For example, a Visual Basic 6 Service Pack 5 program is built on Microsoft Windows 2000 Service Pack 2 by using the latest version of MDAC that is present (version 2.6). When the distribution is built, an earlier version of MDAC (version 2.5) is used (unless MDAC 2.6 is downloaded), causing an error 438 to be thrown when the distributed program is run.

Another scenario would be misspelled method or property names, and this scenario is described in the following Microsoft Knowledge Base article:

193265 PRB: VB Doesn't Generate Compile Error for Misspelled Methods

ID članka: 200271 - posljednja izmjena: 12. svi 2003. - verzija: 1

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