REINSTALL Seup - Which Media?

Something/somebody delete some rights assigned to the local groups created by the SQL Server 2005 x64 setup on a W2008 server.  (Perhaps group policy or an admin applied a security script.)  I used the KB910070 slipstream hotfix to do the original install and applied SP3 plus hotfixes.  I need advice on the reinstall.

I attempted a reinstall using the same slipstream media and ini file - with REINSTALL=ALL and REISTALLMODE=omus.  I got an error "The installer has encountered an unexpected error.  The error code is 2902.  Operation ixfAssemblyCopy called out of sequence."  This error was near the end in the client workstation components section.   

I was able to do the reinstall with the original dvd RTM media even though it was not used for the initial install.  Is this okay?  What is recommended?  Do I need to re-apply SP# or the hotfixes?  Should I uninstall and start over?  (This server is not in production yet, but I need it to replace a failing server.) 

What sort of things (e.g., configuration, default locations, etc.) do I need to reconfigure after a re-install? 

Thanks,
Randy

PS Is there an easy way to backup the local group permissions so that I can restore them if this happens again.