UDF error (entrypoint could not be found)

I am trying to access an external function in Firebird, but get this error:

invalid request BLR at offset 59
-function CALCEXPR is not defined
-module name or entrypoint could not be found

I am using rfunc.dll and it seems to be finding it.. though I cannot be sure.

I am testing with CalcExpr, but none of the other functions in rfunc.dll are accessible either.

I am a novice with Firebird - what am I doing wrong?

Thanks

Have you put rfunc.dll in correct subdirectory ?
Has Firebird allowed access to this directory (in firebird.conf) ?
Have you used correct entrypoint names (they are case sensitive) ?
Have you verified that Firebird is really trying open correct dll (e.g. using FileMon from Sysinternals tools) ?

Ivan
http://www.volny.cz/iprenosil/interbase/

Sorry for reviving old thread but i head the same problem and was able to resolve it. So for the benefit of the Internet community here are my 2 cents.

I was running 64 bit Firebird server and was getting similar error for a function that used rfunc. Then I switched to 32 bit version and everything started working as it supposed to. My guess is that my shared library rfunc was compiled for 32 bit server only. I guess it needs to be recompiled if you want to use 64 bit.