Guys, please, go over the opcodes again, and do not provide people with wrong information.
"C3" is the "ret" opcode; the correct one (for "int3") is "CC".

logicalbit,
try changing the radiobuttons settings in the "Debugging" tabsheet, then deselect and re-select the checkbox "Prompt for missing source files", and load the program again.
This works on my systems (Windows 2000 Build 2128 with DS25 and Windows 2000 Build 2195 SP3 with DS26)
Let me know