installing sql server 2008 32bit on 64bit os
Yes it is possible to install SQL Server 2008 Standard 32bit on Windows 7 x64, but only the Professional, Ultimate, and Enterprise editions of Windows 7. You need SQL Server 2008 SP1 though, and cluster installations aren't supported. SQL Server 2008 Enterprise will not install on Windows 7. Microsoft have some doco on MSDN about it.
But as outlined in the comment above - the 64bit version of SQL Server is a much better choice.
What version of SQL Server is it? And what is the error?