too long to allocating channel for rman backup

Hi experts,

This is my case:
backup the oracle database on aix 5.2 (with networker client 7.2.1,
NMO 4.2installed )
networker server: 7.2.1 win2k3
after paste the rman script below

run {
allocate channel t1 type 'sbt_tape';
allocate channel t2 type 'sbt_tape';
allocate channel t3 type 'sbt_tape';
allocate channel t4 type 'sbt_tape';
send 'NSR_ENV=(NSR_SERVER=legatoserver,NSR_DATA_VOLUME_POOL=mypool)';
backup filesperset 10 format '/FULL_%d_%u/' incremental level 0 database
plus archivelog skip inaccessible;
release channel t1;
release channel t2;
release channel t3;
release channel t4;
}

it takes 30 minutes (too long) to give the warning:

Networker: cannot contact nsrexecd service on mycomputer

and then it begins to rman backup successfully

I dont know why there is above warning, this affects on the time to
allocating channel?

I tested rpcinfo -p, ping, backup file from Networker GUI on this machine.
Everything is OK excetp the above issue.


I tested on another oracle database, but it immediately backuped after
pasting the rman script

Thank you so much for your help