"Sometimes" problems almost always depend either on things we don't know about the data, or result from issues that strictures will pick up for you.

For a start add use strict; use warnings; to your code then fix up all the errors that that shows up. If you still have problems trim the code down so it either doesn't use a database, but shows the problem, or use the trick shown in I know what I mean. Why don't you? to include enough of a database to demonstrate the problem in your sample code.

While you are generating the next itteration of the sample code remember to trim out all the extranious cruft. If the problem isn't in the CGI stuff, omit the CGI stuff. We can't try your code if it depends on stuff we don't have (including data we don't have).