Duck and Cover

ok im having a problem with the save game editor(f2ie.)..i started a new game and i saved it....i wanted to test out this mod..(forgot whats it called long something mod....it has a grenade launcher in it)....
i try to replace the spear with the grenade launcher(i changed vaules in the inf)...but i keep getting this problem...where it crashes if i have the weapon equiped and i try to move...if i try to attack my guy dissapears...whats wrong...is it because im on windows exp? or is it something else

alright

peace

I don't use heavy weaponry, so I can't be sure, but it sounds like there might not be a sprite for the character to have that weapon.. At least, that's the first thing that comes to mind.

I don't know the exact problem, but it has happened to me before. Try making a new game in Fallout 2, then use the inv. editor to change the spear to a Wakazashi blade or whatever it's called. Try to equip it, and you'll go invisible, and at some point crash.