Blackberry Enterprise Server (BES 4.1) Install Issue

So trying to install BES 4.1 on a SBS premium (I know not the best situation but thats what the client wants).

Anyway we try to install and get the following error: Faulting application Setup.exe, version, faulting module ntdll.dll

Well so we start thinking ok maybe its Antivirus or something else using the DLL, maybe a permission issue….. NOPE, turns out that BES install doesnt like multiple IP address on 1 NIC, we simply removed the extra IP from the external interface and viola install works without a hitch!