The inv.b0 file keeps track of things you have equipped and things in your inventory. It is mixing the inventory files from different saves that caused the problem, so new equipment should be fine, as should anything you left on the ground or stored in chests.
Any missing quest items, teleporter stones, etc can be replaced (if you don't have both teleporter stones in your inventory when you hit the gong, replacements will be provided anyway, which you can find near the start of the wastelands).
Lost Items - guide and directory of inventory filesI tested replacing the inv.b0 file in one of my save with that from a new save some time ago (when someone else had this problem), and lost everything I had equipped. My previously empty weapon and armour sections had various pieces of equipment, I ended up with different potions and in the miscellaneous section, my pile of gold, a couple other things and a teleporter stone were replaced with 4 piles of gold.
Everything stored in chests seemed to be fine, though, so if you kept backup equipment at your home base, you may not have to do as much replacement to get your character functional again.
