Yes, I made sure to read the documentation very closely but it didn't seem to shed any light on this particular error

I wouldn't expect that it would. XML::Validator::Schema has terrible failure behavior. If it's trying to process a schema which is doing things it can't support it won't generally give you much help figuring out why.

I hope the following .xsd snippet will be helpful

Not particularly... I don't see any place in that snippet where a simpleType is the (direct) child of a complexType. Are you sure you've found the problem?

Here's what I need if I'm going to find and fix this bug:

• A small, complete XSD file containing the problematic construct. No more than 20 lines would be ideal.
• A small XML file which you posit should validate against the sample XSD. Again, smaller is better.

In some cases I can create these myself but you haven't given me enough information to do the job.

Thanks,
-sam