Wordshark and Numbershark work in similar ways. Most of the following error messages apply to both programs. These error messages are based on Wordshark release 3s.05 and later. Earlier releases have minor differences.
Symptom: Our program gives the error message below: “Invalid characters in names”
Further Symptom: Clicking on the icon “OK”, nothing happens
Possible Symptom: You may recently have experienced a Windows system message "you are running with very low diskspace", but actually have plenty of disk space remaining on the c:\ drive.
Typically, the error message will return incorrect characters, for example you entered \ or > but the error returned %
Reason: You do not have enough disk space to open files OR you have too many items on the root of your c:\ drive.
Solution:
Remove unnecessary files from the root of the C:\ drive, and from the desktop.
Remove other files from your C:\ drive, aiming to have at least 20% of drive space free.