It's important that when you install SQL Server Reporting Services on a separate server from the SQL engine, you need to use a compatible version. Obviously you should try to use the same edition, but if you are using developer editions etc and connecting to corporate data sources this may not be possible. Note also the very tight restrictions for the Workgroup edition.
Specifically, the following versions are compatible:
|Evaluation||Standard; Evaluation; Enterprise|
|Developer||Standard; Developer; Enterprise|
You don't want to get to the end of a Reporting Services install, only to then find that you can't connect to the SQL Server you need.