Rename both the save file and the rom exactly.
for example:
Pokemon Pearl.nds
Pokemon Pearl.sav
If youre using Wood Firmware, make sure you have enabled both nds.sav and .sav compatibility =)
Hope this helps out
You could also wait for the TN- CF by total_noob which is suposed to work with the latest firmware. As i said, its not out yet.... but check this page if you want to know more about it.
http://www.psp-hacks.com/2010/11/03/tn-a-exploit-works-on-6-30-and-6-31-too/#comments
error comfirmed here too...
im also using an r4
lets just wait until someone else with other types of cards report the problem to see if its a bad dump or not..