i hv not used proteous in that way so unless u know it vry well, you can add more prblems instead of solve them!
ur reslts cn happn eg due to ur exact new code 
this is y i wud use serial tap – no new code needed!
remembr p18f877a uart rx fifo is very small – mayb u need to chk for rx over run, if u do to much than just rx chars