"CATEGORY MUST HAVE A TITLE" but it does... help?

[Gel]

I keep trying to create a new category, and I get this error message:
Save failed with the following error: CATEGORY MUST HAVE A TITLE

However, I HAVE given it a title. I tried multiple titles and aliases, but nothing will work.
Help?

Also, I don't know if it's significant, but this shows up as well when I try and create a new category (not as an error message in red though.):

Warning: Invalid argument supplied for foreach() in /home/gela/public_html/libraries/joomla/database/database/mysqli.php on line 727

I'm fairly new to joomla, so I apologize if I'm simply missing something simple.

[Benno]

Hi,
If you use Phoca Download for joomla v1.6 see: viewtopic.php?f=31&t=12731
If you use Phoca Download for joomla v1.5 see: 1. Data https://www.phoca.cz/documents/2-phoca-g ... em-solving
Kind regards,
Benno