This is what is called SMC (self modifying code). What it means is that the code is actually modifying part of itself (usually data, but I guess it could be actual code as well). Anyways, I think the TiOS is supposed to prevent this. Are you using Noshell?

Yea, I think there is something in the options. However, unless this prog is something you are only using for yourself, you need to either compile it for something other than DCS (which might make it not use SMC, but that's just a guess), or have a sub-routine that initializes all the data, call it on the actual initialization, then Goto it when you want to exit (so the Return will act as the final return)
...
sub(IN)
...
Goto IN

Lbl IN
.init data
Return