Spaces in file names giving me L204 errors from BL51

I am attempting to use the BL51 linker from the command line using the following as input:

c:\Keil\C51\BIN\BL51.exe C:\Documents and Settings\fya\My Documents\Design05\main.OBJ TO C:\Documents and Settings\fya\My Documents\Design05\Design05.hex IX

But I get the following output:

BL51 BANKED LINKER/LOCATER V5.03 - SN: K1S7U-T9879U
COPYRIGHT KEIL ELEKTRONIK GmbH 1987 - 2002

*** FATAL ERROR L204: INVALID KEYWORD POS: 17 C:\KEIL\C51\BIN\BL51.EXE C:\DOCUMENTS AND #

I tried putting quotes around the file names, so that they would be passed in as single arguments, but I get the same error message.

Additionally, I ran an experiment using the uVision2 IDE. I created a project with an object file in it and had it link. I then looked in the resulting M51 file to find the linker command line. It looked as follows:

C:\KEIL\C51\BIN\BL51.EXE W:\Design 01\main.obj TO My Spaces RAMSIZE (256)

The linking was successful. I then tried to link from the command line using the above and got the following:

BL51 BANKED LINKER/LOCATER V5.03 - SN: K1S7U-T9879U
COPYRIGHT KEIL ELEKTRONIK GmbH 1987 - 2002

*** FATAL ERROR L204: INVALID KEYWORD POS: 22 C:\KEIL\C51\BIN\BL51.EXE W:\DESIGN 01\MAIN.OBJ #

I assume BL51 plays nice with files that have spaces in their names, since I am able to link files with explicit spaces through the uVision2 IDE. Any hints as to what I am doing wrong here?

Thanks,

Ian