Fatal error: Cannot use string offset as an array ...

Shortly after updating my Drupal 5.3 to Drupal 5.5 I noticed (although the problem may have been there earlier) that if I tried to view a comment on a node I received an error similar to "Fatal error: Cannot use string offset as an array in ../public_html/includes/theme.inc on line 555". After searching the Drupal forums I found the following thread: http://drupal.org/node/102440

I looked at my custom theme but did not find any references to the code mentioned in that thread, and I'm also not using the Category module which was suggested. One of the posts mentioned looking at modules that generate links and that made me think of Forward. After disabling the module the error went away. I am not sure if this is helpful but I just wanted to bring it to your attention in the event that the issue does in fact relate to your module in some way. It's a great module so I would love to get it working again. Please advise if possible. Thanks.