> HTTP/1.0 400 Bad Request -- UndefinedObjects are not indexable

This error message is associated with sends of #size to an object that is nil.  In the past, #size used to work fine with scalars, returning 0, but was recently changed (about 2.3-2.4) to return an error when any non-indexable value receives the #size message.

Usually, the message *is* indicative of a logic error, but you can often make old code that once appeared to work continue to work as usual by replacing the offending:

	foo size = 0

for example, with:

	foo isNil or: [foo size = 0]

or a similar contrivance.  Alternatively, you can also try to study the code, identify the "real" underlying bug and fix it.