The following SRPM's for RedHat 6.2 were made with RPM4 and thus cannot be used on RedHat 6.2: fetchmail-5.5.0-2.6.src.rpm usermode-1.37-1.6.src.rpm
Try using RPM 3.0.5 which has forward-compatibility for RPM4.
Yes, it does. However, what you probably don't realize is that it also uses RPM4 semantics in the macros file. This breaks many RedHat 6.2 SRPM's. So that's not an option.
rpm 4.0.2 has been released as an erratum for RHL 6.2. This package works for me fine in 6.2. I do not see a bug here. I think this bug can be closed Nalin, but I'll leave that for you to decide.
rpm v4 is an update for RHL 6.2, you need to install that.