cant install forum ,guestbook

hi
i have cpannel control on my website.
when i want to install advanced guestbook or forum
from menu,despite previous times i get this errors:

1.for guest:AdvancedGuestBook 2.3.3-1 Setup
We are installing in /home/malavann/public_html/new...
There was a problem with the install!

and guest is shown bad like : www.malavan.net/guest

2.buletin (forum) :phpBB 2.0.17 Setup
We are installing in /home/malavann/public_html/for...
The Install is done!
You can access your new phpBB forum at: http://malavan.net/for/
Here is your administrator login information:

but forum doesnt work: www.malavan.net/forum

can help me?
thank you

Yes as far as your phpbb forum. It is instaled just do this. insure both the install/ and contrib/ directories are deleted

As far as your guestbbook you need to put the correct information into your config.php file.

And also next time ask on the phpbb forums about problems for that since this site does not deal with that program.