I have tried putting rfunc.dll in the same directory as the dll, then tried
putting it in the UDF directory, then in a directory specified in the
firebird.conf file ... but none of these approaches works.

Currently my firebird.conf file contains the following line:

UdfAccess = Full UDF; f:\;

And there is a file in the f drive:

F:\rfunc.dll



Ideas?

Thanks,

Aaron