set up iSeries as linked server on SQL Server Express?

I'm trying to play around with SQL Server Express in order to see if we can make use of it to sync some data files to/from our iSeries (V7R1). I've downloaded and tried both Express 2008 and 2012 RC0, but I've hit roadblocks with both.

Apparently, the actual DB/2 connector only works with the paid version of SQL Server--not Express. So, I tried setting up a DSN via ODBC and trying to set it up that way. More failure. I discovered that I *could* create the linked server connection via a script! It shows the iSeries as a linked server which I can drill down into to see the files in the library I told it to use. But, trying to do an actual select query (for instance) on one of the files yields a "catastrophic error" message. :/

Has anyone had any experience setting this up? What am I doing wrong (aside from telling me to buy SQL Server which isn't an option since this testing is my proof-of-concept to justify a potential purchase later)?

Here's the script I've tried to use to create the linked server connection (details redacted):

USE main_db
GO
EXEC sp_addlinkedserver
@server = 'iSeries',
@srvproduct = '',
@provider = 'MSDASQL',
@provstr = 'DRIVER={iSeries Access ODBC Driver};SYSTEM=275.96.445.92;DBQ=mydefaultlib'
GO

And the error:

Msg 7399, Level 16, State 1, Line 2
The OLE DB provider "MSDASQL" for linked server "iSeries" reported an error. The provider reported an unexpected catastrophic failure.
Msg 7330, Level 16, State 2, Line 2
Cannot fetch a row from OLE DB provider "MSDASQL" for linked server "iSeries".

Thanks in advance!

--Luke G.