cmAudioFile.c: Fixed bug in cmAudioFileCreate() where error msg did not

report the name of the audio file which produced the error.

cmAudioFile.c

       ext[i] = toupper(ext[i]);
 
     if( strcmp(ext,"AIF") && strcmp(ext,"AIFF") )
-      cmRptPrintf(p->err.rpt,"The AIF audio file '%s' is being written with a file extension other than 'AIF' or 'AIFF'.");
+      cmRptPrintf(p->err.rpt,"The AIF audio file '%s' is being written with a file extension other than 'AIF' or 'AIFF'.",cmStringNullGuard(fn));
       
     cmFsFreePathParts(pp);
   }