The great thing about Drupal is that it comes with a variety of themes available to download. If, like me however, you want to carve out your own theme then there is an incredibly useful way of doing this: the Zen theme.
Zen is a perfect starting point for anyone who wants to give theming a go for Drupal sites. It is well documented and within a few easy steps you can be on your way to creating your own theme.
I am a great fan of the zen theme & creating subthemes using it too, in fact all my Drupal work uses the Zen Subtheme structure. When it came to recreating my site using Drupal 6 I downloaded Zen and got to work styling and editing my own theme and all was well.
That was until I took the site live: when taking the site live I turned the 'Rebuild theme registry on every page.' function off (recommended as to increase performance) and when editing pages was faced with the following error:
* warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'theme_filter_tips' was given in *path_to_my_site*/theme.inc on line 617. * warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'theme_filter_tips' was given in *path_to_my_site*/theme.inc on line 617.
Now, after searching around on google for a solution I came up with a couple of potential fixes: the first was to clear the site cache under admin>>site configuration>>performance. No Result and the error remained.
BANG.(That was when it hit me.)
I had named my Zen subtheme: 'theme'. I am still not sure what was going through my mind when I did but hey thats another story.
To fix the problem I copied my entire theme into a new folder and named it something new i.e: 'supertheme' then had to go through the .info & template files and change the name to: supertheme and the instances of 'theme' to supertheme.
The problem was no more.
So to sum up: don't name your Zen Subtheme: theme.
At least I hope it is. If you do notice any issues with the site then do comment and let me know :)