You are being asked for the second CD if you manually add stuff (or force HFSLIP to add stuff) like "filename.exe = 2,,,,,,,1,0,0" into the txtsetup.sif of a Windows XP source. Most often, the "2" is intended for a Win2K install; the equivalent of that for Windows XP and Windows 2003 is "100" but it's better to use "1" which is compatible with 2K, XP and 2003. Ah, wait... That's most certainly a problem with your custom winnt.sif file...