If you are using IDLE then try using command line. This problem seems to be fixed in IDLE 0.6 and newer. If you are using an older version of IDLE try upgrading to Python 2.0 or newer.
Email me and ask. Helpful things to include are what you were trying to do, what happened, what you expected to happen, error messages, version of Python, Operating System, and whether or not your cat was stepping on the keyboard. (The cat in my house has a fondness for space bars and control keys.)
What and when was the last thing changed?
2000-Dec-16, added error handleing chapter.
2000-Dec-22, Removed old install procedure.
2001-Jan-16, Fixed bug in program, Added example and data to lists section.
2001-Apr-5, Spelling, grammer, added another how to break programs, url fix for PDF version.
2001-May-13, Added chapter on debugging.