I’m having a similar problem. When I try to tag a post nothing happens. No error message, but no tag either. Using v. 2.8.1.
(fyi, tags added before the upgrade to 2.8 function properly)
I’m not sure if this is exactly the same problem, but even after installing 2.8.1 I can’t edit comments. I get this error message when I try:
Warning: array_merge() [function.array-merge]: Argument #1 is not an array in /home3/unlyingl/public_html/wp-includes/comment.php on line 1097
Warning: Cannot modify header information – headers already sent by (output started at /home3/unlyingl/public_html/wp-includes/comment.php:1097) in /home3/unlyingl/public_html/wp-includes/pluggable.php on line 865
Any suggestions, or will this be fixed in a future update?