Source system activate/restore

I have created an R/3 source system in BW. Have checked SM59, WE20, WE21 many times and could log on to the source system. Have also replicated the source system. However, when trying to activate or restore the source system I keep getting:

First, the status message: Update source system application component hierarchy

Second, RSAR error 375: Result of the destination check: Timeout

And the activation is terminated.

My OSS Note 140276 search yielded nothing as well.