Can't export in 3.0

I just installed 3.0 and find I can’t export. When I try, I don’t get the file to save, as usual, but a new page listing out all the blog’s content, with a bunch of error messages at the top of the page:

Warning: Illegal offset type in isset or empty in /home/mysite/public_html/wp-includes/taxonomy.php on line 176

Warning: Cannot modify header information – headers already sent by (output started at /home/mysite/public_html/wp-includes/taxonomy.php:176) in /home/mysite/public_html/wp-admin/includes/export.php on line 44

Warning: Cannot modify header information – headers already sent by (output started at /home/mysite/public_html/wp-includes/taxonomy.php:176) in /home/mysite/public_html/wp-admin/includes/export.php on line 45

Warning: Cannot modify header information – headers already sent by (output started at /home/mysite/public_html/wp-includes/taxonomy.php:176) in /home/mysite/public_html/wp-admin/includes/export.php on line 46

Any ideas about what my going on here?

Thanks.