All right to clarify the RAM and jumper thing once and for all:
Jumper 213 selects the Chip-RAM size. Set so 1-2 it will only accept a 2MB Module, set to 2-3 it will accept an 8 MB module useing only 2 MB. If you insert a 4MB module it will only be recognised as 1 MB.
Jumper 852 selects Fast-RAM size. Set to 1-2 it will accept 4 MB modules only, set to 2-3 it will accept 1 MB modules only
Though there is an undocumented feature thet when jumper 582 is set to 1-2 you could use two 8MB modules instead of 4 4MB module if you place them in bank 1 and 3.
If all this doesn`t help you have to face the fact that the leaky battery allready killed the Fast-RAM at some point.
Don`t bother with RAM on a Fastlane, DKB3128 or even on a ZII card. It is even slower then the A4000 motherboard RAM. Though it is a nice goodie if your accelerator is allready packed to it`s max of 128 MB. (I got an A3000T with 320 MB Fast-RAM using an DKB3128 and a fully populated Fastlane in addition to the 128 MB on the MKII)