Michael,

I have experienced similar problems about a year ago.
See:
http://www.picbasic.co.uk/forum/show...ghlight=eeprom

It was fixed with one the updates.

And I can confirm what Melanie has already said:
Using PBP 2.45 and MPASM 4.01 with WinXP Pro, I can confirm the EEPROM works fine with 18F242, 252, 2420, 2520 and 2620. No blank spaces, odd and even locations accessed.
I have tried it with the latest Versions of:
PICSTART+
ICD2
MicroCode Loader