Invalid argument supplied for foreach() ... taxonomy.module on line 1214

Testing so far shows that this has something to do with using wordpress import module and vbulletin import module together.
If I run wp import w/o vbtodrupal, I don't get the error. The reverse is pretty much also true. So it seems. Testing this is very time consuming but I've seen it happen once going each direction.

OK, found a workaround.
Apparently what's causing the error is that there are some nodes somewhere that "lack the taxonomy attribute"? ...er, something like that.
In my lingo: some slightly (I hope) broken nodes. So when taxonomy module tries to index, can't.
I hope to figure out what this looks like in the database and do some search and replace so I can remove the core hack that prevents the error.

Core hack here: http://drupal.org/node/259632

Of course, I really have no idea if the broken nodes are from the wordpress import or the vb import or even both.

I use neither of these modules and my log gets 23 of these errors each cron run.

+1
I have same issue, but neither of these modules, handfull on each cron run

+1
Same issue/error in log, but none of the two modules installed. (Did this appear after upgrade to views 6.x-2.6 ?)

In my case, the problem turned out to be corrupted data. Not clear how that happened since I was attempting multiple imports and also had to do some direct database hacking. ... only discover that I'd broken it bad somewhere along the line.
So we went back to clean data and skipped the imports and we no longer see this error at all.

It is definetly problem of bad imports... I discovered this problem only in moving to D6, I didn`t notice problems on d5.

So, my solution: I remembered that one time I was experimencing with import modules on live site. That time I simply deleted data from node_revisions table. That was ok for D5. Now I realized that in my tables was still data from bad imports and I deleted data from node table also.

yes, I now, this is "dirty" method, I should use special snippet - but I don`t know it :)

So, revise your database and be sure that numbers of data in node and node_revision tables are the same.
(please sorry my English as I`m not a native speaker)

I've seen this in Drupal 5 also. It's annoying and tricky. What I need to know is: precisely what data is causing the problem. It seems here the problem is just that the node is missing the taxonomy variable. Can someone confirm that's what is happening? And that in the database the node isn't attached to any taxonomy terms? Also, exactly what module the nodes were imported by.

If the problem is vBulletin has posts/threads which are not attached to any forum, then which forum should we attach them to? Maybe create an 'orphan threads' taxonomy term under forums or something. Curse you vBulletin! :)

subscribing

I'm getting this too, after a large import of data, but not using the vBulletin to Drupal module.

Here is an active thread related to this topic: http://drupal.org/node/259632