WASP is running on top of Firefox and many different things can be responsible for a page halting a crawl and you can try the following things:

• Try to disable extension such as flash and silverlight specially if you are running old version of those.
• Disable also any other Firefox extension/plugins
• If the crawl or Firefox hang, you can use the resume feature to resume your crawl
• Filter out extension that Firefox open and try to save
• Filter out page that ask to print