Is that the code you get when running the sample?
Or you made some changes?
Took a look at the wa_appbuilder_php.php file looks like its coming from that file, that file is in the webassist folder under database_management. Wierd cos it should be included:
<?php require_once("webassist/database_management/wa_appbuilder_php.php"); ?> and not show up when you looking in a browser.
Look like i missed some files in the zipping of the sample, so i reupload it. :)
I tryed to run the sample without the missing files, and it worked fine, only thing not showing was the menu. But insert Main Cat and Sub Cat worked fine.
Keep me posted on your progress, :)