Code banking

The keil micro vision help files say that up to 64 code banks are allowed using LX51 linker/locator. I'm getting this error message when i try to use 64 bank registers:

*** ERROR: ADDRESS OUTSIDE INTEL-HEX RANGE (USE 'H386'CONTROL)

What does it mean exactly?

Also, is there any way to use more than 64 banks? Modifying the L51_BANK file?

Thanks.