gdb does not display source code

gdb does not display the source code in xemacs 21.4 in windows me.  i have also
experienced the same problem in rh9.

when i run gdb (sometimes using M-x gdb and sometimes, using the toolbar) while
the source code is open, gdb opens in a new buffer hiding the buffer containing
the source code.  when i run the program in gdb, the program runs in an ms-dos
prompt and nothing happens with gdb until the program ends.  when the program
stops at a breakpoint, the gdb buffer splits where one buffer (buffer 1)
retains gdb and the other buffer (buffer 2) is in Fundamental major mode and
gdbsrc minor mode.  buffer 2 is blank but i can issue commands to buffer 1 by
just typing a key (like n for next.) the key pressed is not displayed in buffer
so it remains blank.

i hope there's an easy solution for this problem.  you can also point out what
i'm doing wrong.  i'm an (x)emacs newbie. thanks in advance