Unfortunately, you cannot do that (though I agree it would be nice sometimes :-) ). You can approximate it though, by using the "R" command in the debugger, which restarts the program using the same command line arguments and keeping all breakpoints you have set. So in your case, once you realize the problem was line 105, you could do:

<db> b 104      ## set a breakpoint before your problem
<db> R          ## restart keeping breakpoints
<db> c          ## continue to first breakpoint at 100
<db> c          ## continue to breakpoint at 104
[download]

and then you could use whatever other debugger tricks you want to figure out what is going on.

Of couse, you could also delete your breakpoint at 100 first and avoid needing the second "c" command.

Hope this helps...

--JAS