I am going to submit this as a bug report as well, but I wanted to share this on Pronet, as it may save other MT consultants/developers the hours of support time that I have spent on this issue. I have seen this 3 times with user of plugins, and it can be difficult to diagnose.

In short the problem seems to affect people:

- who upgrade to MT4 from a previous version of MT,
- AND who used dynamic publishing before and after the upgrade,
- AND whose path to MT4 is different from the path to the older version (for example, before the upgrade is was /var/www/cgi-bin/mt and after it was /var/www/cgi-bin/mt4)

The problem is that the old mtview.php (in the blog root directory) does not get updated. The side effect is that the mtview.php file is still pointing to the pre-MT4 directory, point to the old mt-config.cgi and the old mt.php file. In many cases the old versions of these files still exist at the old paths, because when people upgrade they often upload MT4 to a new directory, leaving the older MT in place -- this makes this problem difficult to diagnose, because MT4 is read a valid config file and valild mt.php library -- it doesn't know that it has the old files.

Things can get even more confusing when the old MT config file points to a old, pre-upgrade version of the database that still exists -- one user of Fast Search was stumped (as was I) when after upgrading to MT4, his search results included only the pre-MT4 entries -- there were no error messages at all, but the search was being handled by the older version of MT against the older version of the database!

Another symptom of this problem is when MT can't seem to find certain dynamic template tags. Errors like:
Smarty error: [in mt:17 line 23]: syntax error: unrecognized tag 'MTTemplateTagName' will result, even though the php files may be in the correct location.

Part of the problem here stems from the fact that MT4 got "smart" and no longer included the "dynamic bootstrapper" template with each blog, that built the mtview.php, but rather built it behind the scenes when publishing settings are saved. The side effect was that the file didn't get rebuilt with indexes, as was the default in previous versions. It was also "out of sight, out of mind" with MT4. While the MT4 upgrade includes an upgrade task to remove the mtview.php bootstrapper, it does not delete the the old mtview.php file, nor does it attempt to update the existing mtview.php file(s). :( I think (but am not sure) that saving the publishing settings for blog will attempt to update the the file, but who changes there publishing setting after upgrading?

If you or a client run into any strange dynamic publishing issues under MT4, I recommend the following as one of the first troubleshooting steps:

1. Rename the existing mtview.php file.
2. Save the Publishing settings for the blog. This should recreate the mtview.php.

I hope this helps save others from the hours of frustrating troubleshooting that I have ensured on this....