SQL Server Setup Failed to compile the Managed Object Format (MOF)

I’m trying to load a copy of ACT 2008 Premium but I’m getting this error. What can I do to resolve this?

TITLE: Microsoft SQL Server 2005 Setup
——————————

SQL Server Setup Failed to compile the Managed Object Format (MOF) file C:\Program Files\Microsoft SQL Server\MSSQL.2\MSSQL\Binn\sqlwep-xp.mof. To proceed, see “Troubleshooting an Installation of SQL Server 2005” or “How to: View SQL Server 2005 Setup Log Files” in SQL Server 2005 Setup Help documentation.

For help, click: http://go.microsoft.com/fwlink?LinkID=20476&ProdName=Microsoft+SQL+Server&ProdVer=9.00.3042.00&EvtSrc=setup.rll&EvtID=29513&EvtType=sqlca%5csqlmofca.cpp%40Do_sqlMofcomp%40Do_sqlMofcomp%40x8007054f

——————————
BUTTONS:

&Retry
Cancel
——————————

Thanks!

Malcolm