Sounds that there is a problem with the profiles.ini file that stores a link to all the profiles.

• http://kb.mozillazine.org/profiles.ini_file

You can try to delete the current profiles.ini file (if there is one) to see if that helps.
Also make sure that your security software isn't protecting such an .ini file against changes and prevent Firefox from registering the profile.

• http://kb.mozillazine.org/Recovering_a_missing_profile
• http://kb.mozillazine.org/Profile_folder_-_Firefox

i deleted the .ini file and logged on as different user still didnt work

Is there a profiles.ini file created?

Can you list its content?

Does it have a section for the default profile?

there is one

[General]
StartWithLastProfile=1

[Profile0]
Name=default
IsRelative=1
Path=Profiles/ewnyp94u.default

Is there also a profile folder with that ewnyp94u.default name on the hard drive?

You usually get such an error if the profile that is specified if missing.

Vista/Windows 7:

• C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\

Windows: %AppData%\Mozilla\Firefox\Profiles\<profile>\

The "Application Data" folder in XP/Win2K and the "AppData" folder in Vista/Windows 7 are hidden folders.

• Use %APPDATA% in the "File name" field or make sure that you see hidden folders
• http://kb.mozillazine.org/Show_hidden_files_and_folders

there is now cause i created a new profile

Does this mean that you no longer get this error?

for that particular user but when someone else logs on the error comes up again