This is not so easy...
You can't access linked tables with "Seek". So you need to open the database containing the real table:
set dbCurr=currentDB
varDbConnectFileName = dbCurr.TableDefs("LinkedTableName").Connect
varDbConnectFileName = Mid$(varDbConnectFileName, InStr(varDbConnectFileName, "DATABASE=") + 9)
Set dbConnect = Workspaces(0).OpenDatabase(varDbConnectFileName)
Now you can open a table directly in dbConnect like:
set rsToSeek=dbConnect.OpenRecordset("TableName",dbOpenTable)
rsToSeek.Seek SeekString
Don't give up when struggling - it works!