EHP5 Upgrade stuck in MAIN_NEWBAS/RUN_RSAIMMERGE_UPG

Hi,

We are upgrading our EHP4 system to EHP5. In Downtime phase, at job MAIN_NEWBAS/RUN_RSAIMMERGE_UPG the upgrade got stuck.

The Error is "A2EEAIMMERGER 003 Error when determining the tp interface version".

Target kernel stack is 720 sp 120.

tp.exe present in sys\exe and dvebmgs00\exe are not working. When we execute tp in cmd, we are getting below error,

tp=>sapparam(1c): No Profile used.
tp=>sapparam: SAPSYSTEMNAME neither in Profile nor in Commandline
This is tp version 380.03.58 (release 720, unicode enabled)
tp returncode summary:

TOOLS: Highest return code of single steps was: 0
ERRORS: Highest tp internal error was: 0203
tp finished with return code: 203
meaning:
wrong syntax in tp call

Has anyone faced this before. Please let me know how to ressolve this.

Regards,

Siva.