Error Code: 0xe00002fe Cannot log on to MAPI with the specified credentials. Review the resource credentials for the job, and then run the job again

hi,
I removed IPV6 protocol from exchange server. and I receiving the following error. I need to turn off the IPv6 protocol. but I can not make a backup.

I followed these steps (http://seer.entsupport.symantec.com/docs/305539.htm) but could not reach the solution.

I very glad if you share your information.because I need urgent solution :)

i'm using backup exec 12 and exchange server 2007. running on separate machines