As an immediate solution, please try out alpine. This is the designated successor to pine, and shares config files and overall functionality; pine itself is no longer maintained. It this works, we suggest to just continue using alpine in the future.

If you need to identify the offending mail (e.g. because you can't for some reason switch to alpine yet), you can use pine with various terminal sizes to quickly narrow down to the region that has the "bad" mail. Start with a large (vertically) terminal window, note for which message number you start to get the first error message in the (bottom) status line. Quit pine, resize the window vertically, quickly "jump" to a message shortly before the "bad" mail, and scroll down. Repeat until you have the offending mail isolated on a single line, then use some other mail program (or http://cern.ch/mmm) to delete that mail.