I feel your pain, for I lived your pain.  We created hundreds of Crystal Reports against Remedy databases (both Oracle and SQL).  We were unable to successfully utilize the ODBC drivers  kindly provided by Remedy.  We could not link anything (a known feature).  The only way to use the provided drivers is to have a view created of the fields you need, and have that view inserted into the Remedy database instance.  Because our reports were so critical, and the DBAs wouldn't create any views, we used ORANT920 drivers and later, generic SQL drivers and went against the backend.  We deciphered what tables we needed, created our global reports and scheduled everything via BOXi.  We had a great deal of difficulty with historical accuracy using Remedy, so we created a Remedy datawarehouse containing problem management and change management data marts.  It was challenging, but the results were slick.  A word of warning coding on a Remedy SQL database...use "nolock" when selecting, it you don't, you'll get some mad DBAs breathing down your neck when you crash the database! (didn't have that problem with Oracle, tho'!)