Hi all, I generated a .sav file for my IDL program. All features can work in IDL VM except the part that uses "CALL_EXTERNAL" to call some C routines. The error message is "CALL_EXTERNAL: Error loading sharable executable. Symbol XXX,File=XXX.DLL The specified module could not be found." What options do I have to solve this problem? Re-write all C codes in IDL? Thanks.