Firebug Losing Marbles

I've开发者_开发知识库 noticed recently firebug is starting to throw javascript errors about code that it hasn't before. Such as $ is not defined and also errors with Jquery and processingjs core, which i'm assuming is error free.

Anyone else getting this, and should I just ignore it?

should I just ignore it?

Probably not: Errors in reference libraries like jQuery often stem from their functions being called with incorrect parameters.

It's impossible to say more without details, but it is definitely worth investigating why this happens.