Database connection problems after upgrading?

[eluser]Unknown[/eluser]
I run a e-commerce store that I haven't programmed myself, mainly since my knowledge about PHP is just basic. The guy that made it have moved on and cant help me out. Well, to my problem;
I was running Codeigniter 1.5 and my web hosting just upgraded from PHP 5.2 to 5.3 leaving me with a lot of error messages. Google some after this to find out that I needed to upgrade so I upgraded from Codeigniter 1.5 to 1.7.2. Went thrue the steps to do that and it is upgraded to 1.7.2. But now I have some other problems instead.
The error message I get now looks like this:

A Database Error Occurred
Error Number: 1146
Table 'formahantverk_s.Array' doesn't exist
select * from Array where Array="adminuser" and Array=md5("password")

It occurs when I try to login as either admin or a customer. It looks like all the product descriptions and such is loaded from the database, but customers cant login to order and I cant login to check orders or administrate the shop.

With my basic knowledge im having some real problems solving this. Is there something in 1.7.2 that like stores configurations in arrays instead of variables? Or what could be the issue?

I would really appreciate some help. Tried to google it for some time now but gotten nowhere.

[eluser]invision[/eluser]
Have you updated your database data in the config file?

It would be worthwhile looking at this to see if your original details are still in place.

[eluser]Unknown[/eluser]
Thanks for the reply!
Yes everything is still in place there.

[eluser]danmontgomery[/eluser]
You're passing arrays when generating the sql, post the code where you're forming this db query