I tried it with a fresh 2.2 install and the default theme and it worked OK until I tried to change some of the options. It gave me a “Cannot load” error. I found that I needed to put post-teaser.php in the plugins root folder, not in the post-teaser folder.
I did not try it with any other themes. It is working with the default WP theme.
A quick hack is to comment out that entire if statement you mentioned. I also commented out the add_filter for autoopsfix at the end of the file since I believe the issues it fixed have all been taken care of.
With that little modification I’ve had it working fine on WordPress 2.2 and 2.2.1 installs.
The only thing I haven’t checked the functionality of is multipaged posts (which I’ve never used) but otherwise there aren’t any major issues. So, that may help as a quick fix until we figure out exactly what’s going on (I’m just catching up on changes in 2.2 as I still use the 2.0.x line).
My Post Teaser works for the first and second post on a page, displays the full article for the third, works for the fourth, full article for the fifth, etc. On any page. The first two will display a teaser but then only every other one will. Does anyone have an idea how to fix this unique problem?