Sometimes VA parses .asm files and does it incorrectly. It is enough to open .asm and .c/.cpp/.h files in IDE. E.g. C:\\Program Files\\Microsoft Visual Studio\\VC98\\Include\\_DBDAO.H C:\\Program Files\\Microsoft Visual Studio\\VC98\\CRT\\SRC\\Intel\\CHKSTK.ASM
Sorry for misleading. "VS60" is Visual Studio 6.0. I have no VS2003 and can't test it, but VA+VS2005 works perfect.
I suppose you will see many-colored .asm file. Words will be highlighted random in different colors. At the same time VA will be inactive. At least Navigation bar will be hidden.
If I open the only .asm file in IDE, then I see no problems with colors, and the whole text is in black. But after opening some of files that VA can recognize (e.g. .h or .c), the colors in .asm file become invalid.