Datatable cannot be converted to Datatable

[jbeckh2]

Today when I opened a solution, I started receiving this around 205 of
these errors:

Value of type 'System.Data.DataTable' cannot be converted to
'System.Data.DataTable'

These errors were not here two days ago when I last opened it. I do
not believe anyone else has touched the source either.

I'm using the 1.1 Framework (1.1.4322). I've checked all of the
System.Data dll references across the projects in the solution. All
point to the same dll.

I've seen this error before, but it was caused by mixing 2.0 and 1.1
projects. There is no 2.0 references in this solution. Actually, 2.0
isn't even installed on this machine.

Any help would be appreciated