I’m using the new mid-century template set and Movable Type Pro. Today I tried to add related entries, first using the code from http://www.devlounge.net/code/related-entries-in-movable-type, then after an error used this code: http://wiki.movabletype.org/Related_Entries (pretty much the same code). I included a <$MTInclude module="Related"$> tag in the entry template, just above the other two includes for trackbacks and comments. When I tried to rebuilt I got the following error:
An error occurred publishing entry 'Do I Need To Go Pro?': Publish error in template 'Entry': Error in <mtInclude> tag: error in module Related: Publish error in template 'Related': Error in <mtentryiftagged> tag: Error in <mtsetvarblock> tag: Error in <mtentries> tag: You have an error in your 'tag' attribute: Movable Type OR Upgrade
After reading all about tags (http://www.movabletype.org/documentation/author/tagging-entries-and-pages.html) I went through all my tags and added quotes, rebuilt all the entries that had those two-word tags, re-added the mt include tag to the entry template, and got the same error.
I’m not sure where I went wrong, and have wasted an entire afternoon trying to get it to work. Any help would be appreciated.
Reported on Movable Type 4.2

Here's that error again for those that don't want to vide the source code:
Can you post the code for the related template.
Hi Rob, I used this code from http://wiki.movabletype.org/Related_Entries
<mt:entryiftagged> <mt:setvarblock name="curentry"><mt:entryid /></mt:setvarblock> <mt:setvarblock name="relatedtags"> <mt:entrytags glue=" OR "><mt:tagname /></mt:entrytags> </mt:setvarblock> <mt:setvarblock name="listitems"> <mt:entries tags="$relatedtags" unique="1"> <mt:setvarblock name="listentry"> <mt:entryid /> </mt:setvarblock> <mt:unless name="listentry" eq="$curentry"> <li><a href="<mt:entrypermalink />"><mt:entrytitle /></a></li> </mt:unless> </mt:entries> </mt:setvarblock> <mt:if name="listitems"> <h3>Related Blog Entries</h3> <ul> <mt:var name="listitems"> </ul> </mt:if> </mt:entryiftagged>I thought from the error that the problem had something to do with my tags.
Glad you added the Preview button.
Hi Toni. Have you determined whether it's related to the tags on a single entry or a problem with the snippet of code itself? If you save/republish an entry with no tags or with one tag do you get the same error?
I published an entry with two one-word tags and got the following error:
Then I tried publishing an entry with no tags and got the following error:
I can't publish the entry template without errors either.
Notice the second error, with no tags? I was still working on the same entry "Post Office Plugin". MT has quoted the previous entry in my list which I was not publishing. Maybe this is a javascript error?
Thanks for your help guys, but I've fixed this problem.
I remember reading on the Devlounge post that there must be no spaces in the setvarblock.
eg. I changed the code from this:
<mt:setvarblock name="relatedtags"> <mt:entrytags glue=" OR "><mt:tagname /></mt:entrytags> </mt:setvarblock>to this: