"Could not load file or assembly" error VB.NET

Posted on 2012-03-22
Medium Priority
Last Modified: 2012-06-21
Hi X-perts,

I have a VB.NET project that cannot be built on one particular PC with one particular DLL. The details:

1) I migrated a project to a new Win 7 64 PC (VS 2008).
2) When trying to build, it generates an error:

Cannot register assembly "XXX.dll". Could not load file or assembly 'XXX, Version=3.0.2000.0, Culture=neutral, PublicKeyToken=798276055709c98a' or one of its dependencies. One or more arguments are invalid (Exception from HRESULT: 0x80000003)      

3) I have another version of that DLL XXX.dll, which works fine on that "Bad PC".
4) Both versions of XXX.dll work fine on any other PCs (about 50 tested) except that "Bad PC"
5) Only one version of XXX.dll works on a "Bad PC"
6) .NET configurations are identical on ALL machines.
7) VS references on a "Bad PC" point to the same libraries with the same versions
8) I tried to decompile that XXX.dll with Reflector and it shows references to the same dependent libraries - for both versions:


All the dependencies' versions are the same for both XXX.dll libraries.

My question: what could prevent running one of the versions of that XXX.dll on a "Bad PC"? That XXX.dll is for .NET 2.0, quite old one.

Question by:orgrau9
LVL 40
ID: 37755611
Some 32-bits dlls do not work well with 64-bits applications. That might be causing your problem.

In the project's properties, in the Compile tab, under the Advanced Compile Options button, try setting the target CPU to x86 so that your application will compile in 32-bits.

Author Comment

ID: 37755724
32-bit is not a problem. First, i tried changing Compile Options to x86 - no difference.

Second, my other win 7 PC is also 64 bit, but both DLLs run perfectly.

My first guess was that the "Bad DLL" had difference dependencies versions on the "Bad PC". I checked all the versions - exactly the same on both PCs.

More ideas?
LVL 83

Accepted Solution

CodeCruiser earned 2000 total points
ID: 37765144
>Could not load file or assembly 'XXX, Version=3.0.2000.0, Culture=neutral, PublicKeyToken=798276055709c98a'

Does that version with that token exist in GAC?
Is the assembly COM visible?

Use process monitor to see what files its trying to access


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