VJ, you may want to contact DB2 support to dig into this further. A couple of possibilities come to mind though. If 'rose' already exists on the target system, and you're intending to replace that entirely, then you may want to drop it first and allow RESTORE to recreate it. If you do that, keep a backup copy of all your existing logs and DB's of course. There are also some fairly significant enhancements between FP15 and FP7, so if you've taken advantage of some of the new features of DB2 in FP15 there is a chance that you may not be able to restore backwards to the older FP7.
Hope that helps.