I get an error when processing data in different languages

[eluser]KeyStroke[/eluser]
Hi,

I have a login form for a multi-lingual site that doesn't seem to accept input in multiple languages.

For example, when a user enters his login name in Arabic, this error message will show up:

Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE) for operation '='

What can I do to fix this problem? it's obviously something in my database, but I have no idea what's wrong.

Appreciate your help.