Hi ,
Please double check the following:
– session name is case sensitive . Use the same for Session Name values on both Page1 and Page2
– ensure that the list that you display on Page2 has items that have the value that you filter.
– change the CAML filter condition instead of equal to not equal (or is not null) for testing only.
– for testing purpose, expose the value from the session using the the LinkTo property using the ?Field=<%FieldName%> syntax (see the docs for more details)
When you make click on the Page1 link you'll be redirected to Page2.aspx?Field=value and see the value that is passed on.
Also, please let me know your SP and QA version.
Thanks,