Exchange 2010 SP2 but unable to extract emails attachment

Hi guys..i m using Exchange 2010 SP2 but unable to extract emails attachment and i m not used to operate cmdlet of MS Exchange. Please help me in resolving this issue. This msg shown:

Failed to mount database 'Mailbox Database'.
Mailbox Database 0610509261
Failed
Error:
Couldn't mount the database that you specified. Specified database: Mailbox Database; Error code: An Active Manager operation failed. Error: The database action failed. Error: Operation failed with message: MapiExceptionCallFailed: Unable to mount database. (hr=0x80004005, ec=-515)
. [Database: Mailbox Database, Server: server.domain.local].

An Active Manager operation failed. Error: The database action failed. Error: Operation failed with message: MapiExceptionCallFailed: Unable to mount database. (hr=0x80004005, ec=-515)
. [Database: Mailbox Database, Server: server.domain.local]

An Active Manager operation failed. Error: Operation failed with message: MapiExceptionCallFailed:
. [Server: server.domain.local]

MapiExceptionCallFailed: Unable to mount database. (hr=0x80004005, ec=-515)