7
Hmmmm. Let's see if I can help. I just did this on another site using 2.3.3. Let's see if we can narrow down the problem location. Personally, I haven't seen this error, so not sure what the issue is yet.
The error seems to be in loading the Smarty filter, so did you upload all the xoRewrite files (there is one in the class tree and another in the Frameworks tree as well as the new configs directory)? Are they the same file permissions and ownership of the other files in those directories? Make sure they exist and have proper configs.
Next, if you follow the steps in my article (an overview of others' work also posted here on this site as linked by webmystar in this thread), you should be able to test each part of it as you go along.
We'll assume you did the test of the mod_rewrite module and it works.
First modify the .htaccess file, then test to see if the new URLs work. Assuming they do, then you can move onto the next part -- rewriting.
Initially turn off all of the rewrites in the actual config file and make sure XOOPS will work without any modules being rewritten. Of course, you'll have to make the hack in the header.php file. Assuming XOOPS works without any modules rewritten, then turn on individual modules one-by-one for rewriting.
And then don't forget to clear the cache files.
Confirm all this and maybe give us more info about the configs, a link to the site, etc. Have you turned on debugging?