After WP3 upgrade, unable to add tags to posts

Hang on… I may not have copied everything up to the site..

OK… recopied both folders (in ASCII) to the site and the admin page opens fine, but the tag behavior is unchanged.

If don’t mind, can you install a test blog in a separate directory and separate database and see if you have the same problem there?

From my webhosting (justhost.com) control panel, I clicked their link to install WordPress (which is what I had done when I installed WordPress). That took me to something called Fantastico, which installed what it said was WordPress 2.9.2 into a test folder.

When it was finished installing, I opened a new post and tested the tags. Worked perfectly.

I clicked the link on the top of the dashboard to upgrade to 3.0 and again opened a new post to test the tags. Unable to add a new tag.

I did nothing else — I changed nothing, I added no plug-ins — I didn’t even delete the sample pages and posts.

Here’s something… When I went back to the page, I saw this error right under the post window, where it says WordCount:

Fatal error: Call to undefined function is_multisite() in /home/USERID/public_html/FOLDER/wp-includes/wp-db.php on line 505

I haven’t seen that error before on my “live” blogs.

Try downloading WordPress again and delete then replace your copies of the /wp-admin/ and /wp-includes/ directories with fresh copies from the download.

I replaced the wp-admin and wp-includes directories of my testblog and saw no change. Still unable to add new tags without first selecting an existing tag.

Just to clarify, this is issue is happening on both your existing blog and the freshly installed test blog?

Yes.

I was playing around today and note that I can collapse the Tag window, and when I open it back up, if I TAB, I will get the cursor in the entry box (on any installation — they are all behaving the same).

Have you tried this in any other browsers and on any other computers?

I can try it on a Mac with Safari today.

Alright, give it a shot and let us know how it turns out. Good luck!

Works on a Mac with Safari.

Then there’s definitely a problem with your primary browser. Make sure that JavaScript is enabled.

“Allow scripting of Java applets” is (and was) enabled.

I am using IS 7 on Windows XP.

I also notice that if (after selecting an existing tag to get the cursor into the field) I type a tag and then highlight it and press backspace to delete it before saving it — I get the message asking if I’m sure I want to navigate away from the page because if I do, all unsaved data will be lost.