PIC 18F2550 CONFIG BITS

I have a PIC programmer based on the WISP628 design, which I have used 
successfully for several years. On my latest project I am attempting to 
program a PIC 18F2550. I had to update the firmware on the programmer, and 
it now appears to program and verify the code, but it won't program the 
CONFIG bits. For example, the first CONFIG word is at 300000; my HEX file 
wants to put 0x25. I can successfully erase the chip, which causes that 
location to read 3F, but when I try to program it reads back as 0x33. Are 
there any gotcha's for the CONFIG bits on this chip?

Thanks,
Jake