Thanks for your response. I've had some time to look at this.
Note that OutputCompression is not a boolean, it needs to be set to "Disabled".
The initial error is:
Error: Sys.ArgumentUndefinedException: Value cannot be undefined. Parameter name: handler
The error from ScriptResource.axd comes from this method starting on line 504:
OK, we have a lead. Here's my related code:
I modified as follows and no longer see the this error.
Thanks for helping to solve this issue!