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COMException by accessing vb6 DLL from ASP.NET

Posted on 2008-06-10
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Last Modified: 2013-11-07
Hi

we're using an Appartment Model Threaded VB6 COM component in a C# aspx webapplication. This works fine most cases. But sometimes it starts to throw COMExceptions.  Only a applicationpool recycle helps to fix it.

The error is:
System.Runtime.InteropServices.COMException: Automation error
The callee (server [not server application]) is not available and
disappeared; all connections are invalid. The call did not execute.

Does anyone have a clue what could be the case here?
Why could this happen?

This happens on a Windows 2003 Server with .NET Framework 2.0 SP1

Thank you!
Regards!
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Question by:moon44
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by:apeter
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Is there any Memory Leakage ? or more  Load causing the problem ?
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by:moon44
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none of my knowledge. The servers are dedicated for our application. The problem does not occure on some heavy loaded machines, but on some with little load.
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by:apeter
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Were able to establish the pattern which is causing the error ?

Are you passing the objects between windows in ur Application ?
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Author Comment

by:moon44
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No, there is no timeframe or usageinfo that could lead to a analogy.

C# calls a function in vb6 dll. In this function an sql-server is connected and a c++ dll is called.
There are only strings passed.
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Accepted Solution

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moon44 earned 0 total points
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It seems like there was a member variable in the vb6 class which caused the problem.
This member was a object of the c++ DLLs class.
I made this member variable a local variable in the sub it was needed in. That way the error disappeared (for now).

I don't know why this causes a problem, but i am fine with it as long as it works.

Thank you!
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