Setup exits when calling a dll

hi,

I try to call a little dll with CallInstDll.
But when I call it, the setup stops and Windows shows a message "you're program has provoked an exception. Do you want to debug".

This dll has been created in C and I can call it from anywhere else (Delphi, Installshield) without error.

Is there something I can try to find why I can't call my dll in NSIS?

Compile it with debugging information and start debugging.

How do I do that?
I didn't found a debugging mode in the help

I am talking about your plug-in, not the installer. Compile your plug-in with debugging information and run the installer from within the debugger (windbg, vs, etc.).

Ah OK.
But I don't have the sources of the dll, only the binary.
I just know that it works fine when I call it from Delphi.

And it is not a plugin for NSIS.
It's a standard dll I use to check license codes.

Try calling it with the /NOUNLOAD switch on all of the calls but the last one.

I call it one time only. Here is my code:

Push $code
CallInstDll "$TEMP\ccode.dll" CheckCode60
Pop $code

Then try /NOUNLOAD just on that one. If it doesn't work, debug.

Well it doesn't work either.
Thank you. I will try to get the sources.