bit of a longshot, but who knows ...

you are now using;
"C:\Program Files\The Creative Assembly\Rome - Total War\RomeTW-BI.exe" -mod:data -show_err"

try using;
"C:\Program Files\The Creative Assembly\Rome - Total War\RomeTW-BI.exe" -mod -show_err"

see if that works, as I play Rome under BI using these command lines and a custom map and can play custom battles just fine ..
(actually I use this when testing; "D:\Rome - Total War\RomeTW-BI.exe" -nm -ne -show_err -mod ... pretty much always ...:D)


G