Replication Manager Problem

I had an RM job that suddenly stopped working with the following error
2009 10 27 13:13:03 EMCRM01 INFO:Replica 2009 10 27 13:13:03 created from application set xxxxxxxx_db_logs, job VPMPRODDBSQLCL_no_Verify by cerbadmin.
2009 10 27 13:13:03 EMCRM01 INFO:Starting RecoverPoint checkpoint of [application set:servername_db_logs / job: servername _no_Verify] at time 2009 10 27 13:13:03.
2009 10 27 13:13:03 EMCRM01 INFO:This operation can take a long time. Please be patient.
2009 10 27 13:10:53 servername 004052 WARNING:Unable to find Invista CLI path. If Invista instances are being used, install InvCLI into the default path: C:\Program Files\EMC\INVCLI\.
2009 10 27 13:10:53 servername 000600 ERROR:Storage device S:\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\MSDBData.mdf could not be located on supported arrays. Please check if there are problems communicating with the storage arrays.
2009 10 27 13:10:53 servername 026051 ERROR:processGetStorageDetails - failed to write Storage Details.
2009 10 27 13:10:53 servername 026607 ERROR:An unexpected internal error occurred: rawMessage::getSessionId - null buffer
2009 10 27 13:10:53 servername 026607 ERROR:An unexpected internal error occurred: rawMessage::getRequestId - null buffer

The workaround to resolve this error is as follows.
Go into the hosts tab of Replication manager, right click on the host you are having a problem with, and select rediscover arrays. Then execute the job again and it should complete successfully now.