Strange Compile

I was having a problem yesterday with a program I was developing  when I 
tried to run it a divide by zero error would occur, but it was pointing to 
a line that was not dividing. 

First thing I thought was somehow I was running an old version, so I 
logged-off/back-on, problem still kept occurring.  I was compiling the 
program using RSE , received the message that it compiled w/no errors.  I 
decided to compile it using PDM and after that I seemed to get the correct 
version of the program when I ran it.   I compared the compile options on 
RSE vs. PDM and the only difference I see is *Eventf, Optimization *Full 
and replace program *yes in the RSE.

Anyone have an idea what was causing the compile in RSE to not replace the 
program?

Thanks

Steve Jones