Akhilesh and Makarand called me today. When they ran Active Responsibilities concurrent program, the log showed this error:
REP-3000: Internal error starting Oracle Toolkit.
This error was not appearing for Active Users program which completed normal.
Metalink Note 467148.1 describes this problem. The note says that Solaris requires window manager for before the X server is started. We use xfvb as the X server. On checking the server for the windows manager twm, I found that it was not running. After starting the twm process, and then starting xfvb (Xsun), the log was clean. It seems that either the twm process died, or someone killed it by mistake.