After finishing the last part of configuration(at least based on the tutorial I followed) which is the gui configuration of horde, imp, turba, I got an error that says "Fatal Error" then underneath "Fobbiden" and another phrase underneath which I dont remember. This happened right after I clicked the "Generate Horde Configuration" button. I closed my browser, deleted the cache, launched it again and point it to myserver/horde. A horde login screen showed, entered my username which was actually the username I am using in my machine(which I am doubtful is right?), but failed to log-in. I guess I should have added a user but it's too late now. 
Here's the tutorial I followed.
Maybe you could point which part I did wrong???
And since we're at it, should I add a user to horde which I could use to log in? If so, how?

Here's the tutorial I followed.
Administration->Setup->Address Book (turba):
- Should we display an import/export link in Turba’s menu: check
- Select any applications that should be linked in Turba's menu: Imp
- Name of client addressbook: localsql
"Generate Address Book Configuration" button.
Administration->Setup->Filters (ingo):
- Select any applications that should be linked in Ingo's menu: Imp
"Generate Filters Configuration" button.
Administration->Setup->Mail (imp):
-Select any applications that should be linked in IMP's menu:ingo,turba
"Generate Mail Configuration" button.
Administration->Setup->Vacation (vacation)
-Choose MySQL as database backend
"Generate Tasks Configuration" button.
Administration->Setup->Horde (horde):
Database Tab
- What database backend should we use? = MySQL
- database server/host = localhost
- Username to connect to the database as = horde
- Password = <something else>
- Database name to use = horde
Preference System Tab
- What preferences driver should we use? = SQL Database
Authentication Tab
- Which users should be treated as administrators ...
=<your_userid> -->>I used my username in my machine here
- What backend should we use for authenticating users to Horde? = Let a Horde application handle authentication
- The application which is providing authentication = imp
"Generate Horde Configuration" button.
Maybe you could point which part I did wrong???
And since we're at it, should I add a user to horde which I could use to log in? If so, how?