We are not using webwork. We are using the Webwork question server, the most recent version as of sometime this summer. MathObjects is installed in the PG macros directory, though these problems don't seem to use it unless it's called indirectly.
The reason I'm panicing is that we have several of these questions. They all seem to be broken, but they were working when we ran webwork 2.4. Now that we are using the moodle webwork question type and the webwork question server, they are broken. Even if I set 'debug'=>1 in basis_cmp, no errors are returned. The student's information is lost, and the question server marks it as wrong.
I'd really like to get it fixed before we run into a load of these problems. Right now, it's only one. In a couple of weeks, it will be many.
Any ideas will be gratefully appreciated.