this is actually as the messages says "diff user and pwd are using". that's why u cant access the filer with administration permission.
from that windows system, use "net use" command to check connections you setup with the filer.....
u can use "net use /delete" to delete the connection on the IPC$ ...
then use "net use \\filer /user:abc", abc is the user has permission to administer the filer.........