InvalidCastException using IQToolKit w/ MySQL

I'm a long time LinqPad and LINQ to SQL user. I recently needed to start querying a MySQL database, and so downloaded and activated the IQToolkit driver (v2.0.6) via the LinqPad UI. I set up a connection and entities were automatically generated as expected.

However, very basic LINQ queries against most entities fails with an InvalidCastException. Here is an example full C# expression:

  from i in Backlogitemejbs
  select i

This throws an InvalidCastException with the message:

Object must implement IConvertible.

There are a few entities I can query just fine. This is a third party MySQL database, and I'm not very familiar with how it is set up, but it does not seem like there should be a way to set up a table that would cause an exception like this from IQToolkit.

Has anyone seen something like this before, or have any ideas what the problem might be?

Thanks.