Compability not possible?

[deciBel]

Your Portal Version: Latest
Your phpBB Type: Standard phpBB3
MODs installed: No
Your knowledge: Advanced Knowledge

What have you done before the problem was there?
Started up a PhpBB 2.0.18 2 years ago
Installed a 3.0.0 forum after a year
Converted all the old forum content to the 3.0.0 forum. With the convertion tool in phpbb3
Upgraded 3.0.0 to 3.0.4 (last week)

Today the forum is running smooth online, no bugs, no errors, no MOD's... And all post both from 2.0.18, and all the new posts (3.0.0-) are all showing.

What have you already tryed to solve the problem?
....almost everything I can possibly think of. Modded files, re-installed forum, even re-modded files several times, tried same files on other servers (with sucsess) up untill i took a "revert backup" inside forum adm. area. The result on my test server: when revert bacup was "sucsessfull", I popped out as admin, and wasn't accepted as admin anymore. Nor could I log in again as admin. (link dissappeard) "Access to the Administration Control Panel is not allowed as you do not have administrative permissions." I tried log in as user. I was logged in until I clicked any links, forum threads, or anything that made the page refresh. Then I got back to beeing a guest. Error message that came up was:

I've also tried to:
install a fresh phpbb3.0.4, in another folder (with its own new database with prefix "phpbb304_"
Sucsesssfully modded with Board3Portal and the 0.4.1 gallery.

Got a backup from my running forum, and restored this backup into the new forum. The restore seems to get "accepted" but No forumposts from running forum is showing. Not even structure.

Description and Message
...so my magic question to y'all is...

My theory is if this Board3Portal MOD isnt compatible with the forum and the gallery 0.4.1 when I've got an old phpbb 2.0.18 that is "converted" correctly into the new phpbb3...(?)

or....what could be wrong with my sql?

[Kevin]

My theory is if this Board3Portal MOD isnt compatible with the forum and the gallery 0.4.1

No, surely not.
The portal is just taking data from the database, it is not modifying anything.
This board and another one of mine (also with the gallery) is also converted from phpBB 2.x.

I guess this is the problem:

when revert bacup was "sucsessfull"

You wrote it yourself - this was the start of your problems.
Did you revert your backup with the on-board phpBB3 database routine?

[deciBel]

Yes, I reverted it via the PHPBB3 Admin panel...

Should I do it directly in the phpMyadmin insted?

[Kevin]

First question - why did you revert it?
Second: do you have a backup, made with a "real" DB tool, like MySQLDumper oder phpMyAdmin?