Well. I've first of all been using this tutorial: http://hce.halomaps.org/index.cfm?pg=3&fid=1408

I convert to mainmenu and remove the vehicles and netgame stuff, and do exactly whatever else is told. I save as ui.map in my tags\levels\ui folder. I attempt to open it and it come up with the following for every tag in my tags\ui folder in my dubug.txt tags\ui\shell\main_menu\multiplayer_type_select\split_screen\pregame\pregame_list_field.bitmap as example.

12.26.07 21:03:16 couldn't read #262144 bytes from offset #172 in local tag 'tags\ui\shell\main_menu\multiplayer_type_select\split_screen\pregame\pregame_list_field.bitmap'
12.26.07 21:03:16 file_read('tags\ui\shell\main_menu\multiplayer_type_select\split_screen\pregame\pregame_list_field.bitmap') error 0x00000026 'Reached the end of the file. '