You may receive the following message from XP Server, when it is invoked by xp_cmdshell or some other extended stored procedure:
Msg 11018, Level 16, State 1: Procedure "xp_cmdshell", Line 2: XP Server must be up for ESP to execute. (return status = -6)
Verify that there is an XP Server entry in the Adaptive Server sysservers table. If you created XP Server in a different srvbuild session than Adaptive Server and you did not specify a related Adaptive Server, srvbuild cannot update the sysservers table. You also need to check verify that the XP server exists in the interfaces file or LDAP server.
Use sp_addserver to add an entry to the sysservers table.