Can Not Disable Replication In SQL7

Hi, guys

I have an urgent problem in replication.

Yesterday I set up a Transaction replication with 1 publication
Server A (publisher)(push)(SQL 7)
Server B (distributor and subscriber)(SQL 7)

The replication was succesful and the suscriber can get correct data.

This morning I found the Red sigh in replication mornitor/miscellaneous agents.The error message is:
"The job failed. Unable to determine if the owner (domain nameuser ID) of job Agent history clean up: distribution has server access (reason: Could not obtain information about Windows NT group/user 'domain name'. [SQLSTATE 42000] (Error 8198))."

I tried to use the 'disable publishing and distribution wizard' to disable this replication, but it did not finish and the screen jusr freeze. I used the task manager to end the task.

then I check the replication monitor, the publication was gone but the RED sigh still there.

I tried to use sp_dropdistpublisher to drop a Publisher
but it said "the server A is not a distributor"

I tried to use sp_dropdistributiondb to delete the distribution database.
but it said "Could not drop the distribution database 'distribution'.
This distributor database is associated with a Publisher."

I tried to use sp_dropdistributor to remove the Distributor .
but it said "Could not drop the Distributor 'Server B'.
This Distributor has associated distribution databases."

Any suggestion? Thank you in advance.

Theresa