Invalid Operand Error

[Rifleman98atm]

I'm trying to use a linked server in MSSQL QA to retrieve data from a MAS90 system. My SQL is as follows:

select * from openquery(MAS, 'Select * from OE_H1HistoryHeader where OrderDate > ''2005-03-18''')

The relevant part being Select * from OE_H1HistoryHeader where OrderDate > '2005-03-18'

I get the following error:
Invalid operand for operator: >

And ideas or workarounds?