i dont know the answer to your question however i can share some of my experiences.......YAY!!!
Every time ive changed the reserve space using afs explorer the game crashes, this happens EVERTIME, so basically i dont use afsexplorer. I use graphic studio, anytime i need to import stuff the afs file is increased automatically and ive never once had an error.
If you have to use afsexplorer (eg. some patches require it) try this it might work:
(lets say we are changing a stadium .base file, and we have to increase the reserved space, remember im doing this on theory i havent actually tried it, not with reserved space anyway

)
open 0_text.afs in afsexplorer
apply patch (or whatever, so now you have increased the reserved space for the stadium)
save afs to new name eg. deleteme.afs
open deleteme.afs in afs explorer, find the changed stadium file that you increased the space for and right click on it and export it to your c:\
now open graphic studio (the latest version ofcourse) open the 0_text.afs file find the stadium file that you reserved the space for in delme.afs, then right click on it and import the file you saved to c:\, graphic studio SHOULD (im not certain) but should increase its size automatically, then youll be able to play the game as graphic studio has never failed me.
give it a try let us know how you get on, if anybody got any other ideas post them. REMEMBER TO BACK UP YOUR AFS FILES!!!! otherwise you'll have alot of re-installing to do!!!!!!
I do tend to get off topic quite easilly so if ive crapped on about stuff that didnt help you then im sorry.........at least it was an adventure!