bad data passed to highlight module

If I search for a string using the double quotes like "hello there", the module passes a bad link for the highlight module resulting in this error:

warning: stristr(): /drupal4/modules/highlight.module on line 23.

The bad url sent is:

drupal4/node/720?highlight=%2Chello+there

%2C corresponds to the comma that should only added when highlighting more than one word.