Kapil..
there are a few things to check:
a. Check the tracefile ( This file will be in the same directory as the activity log). If possible post its contents here.
b. Looks like u are having problems with
JDBC lookups as well.. Try starting the service from the command line. There would be a startup server or the like in the <WAS_HOME>\AppServer\bin folder. And see if this is still a problem
c. Make sure HTTP server is started ( just in case).
Most important for debugging further is the trace file. So.. post it when u can.