Here is the query, it fails with this message:

Server: Msg 107, Level 16, State 2, Line 1
The column prefix 't' does not match with a table name or alias name used in the query.

USE SalesLogix_Training
SELECT account,accountid,userfield10,cltnum,clteng,ClientName FROM SalesLogix_Training.SYSDBA.Account B
INNER JOIN OPENQUERY([RL-SQL02],'SELECT cltnum,clteng,cltname AS ClientName FROM [RL-SQL02].VPM_Test.dbo.clients') t
on left(t.cltnum,15)=left(b.userfield10,15)
where t.cltnum='0804685'

UPDATE SalesLogix_Training.sysdba.Account
SET SalesLogix_Training.sysdba.ACCOUNT."account"=ClientName
WHERE SalesLogix_Training.sysdba.ACCOUNT."Userfield10" = '0804685'