how to get back to upgraded after 500error

Hello.

My previous gallery 3.0.2 was not working any more so Floridave suggested me to update.

So I did following the steps : http://codex.galleryproject.org/Gallery3:User_guide:Gallery3:Installing_and_upgrading#Upgrading

But I made a mistake, I did not copy the correct var folder so when I tried to log into my uploader, I was brought to the installer who told me he found a var but wanted me to create a database, I then realized it was not the right one so I switch it with the correct one and refreshed the page, it brought me to this page : http://www.coquille.org/gallery/installer/

now when I try to reach my website : www.coquille.org/gallery , I get the 500 error message.

Same when I try to reach the upgrader.

I did change my php.ini file but it did not work, I don't know how to edit the apache config.

How could I get back to the upgrader ? maybe with the correct var folder it would work this time ?

thank you in advance for any useful information.

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Gallery 3 URL = http://www.coquille.org/gallery
Version: 3.0.2 (Coollanta)
Operating system: Linux 2.6.18-194.32.1.el5
Apache: Apache/2.2.3 (Red Hat)
PHP: 5.2.6
MySQL: 5.0.77
Server load: 1.31 1.58 1.53
Graphics toolkit: gd
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