I just checked the zotero.sqlite and all other folder-file present in the Zotero folder, none of it are read only , all of it are "you can read andd write" ... teh comp is a iMAc 9.1 with OS 10.5.8 , firefox 3.6.12 and the latest version of zotero
Did you copy the directory from somewhere? Did you check the permissions on the folder itself?
Is this a normal hard drive or an external drive? Are you accessing the same folder from somewhere else (network share, Parallels, etc.)? Is there a zotero.sqlite-journal file in the directory when Firefox is closed? (If so, delete it.) [Edit for posterity: Don't do this. It could result in database corruption, and if it helped it'd be due to some other root cause that needed to be fixed.]
Otherwise, we can't really help you with this—if Zotero can't write to the database it simply can't work.
Also, this isn't an installation. From the error report it appears to be an upgrade. If you don't need the old database, just delete the Zotero folder.
It's the network share that's the problem, either because of a problem with the share itself or because something else on the share is already accessing the database (which is a surefire way to corrupt your database).
You can always copy the data directory to a local disk and point Zotero at it from the Advanced pane of the Zotero prefs.
I copied the zotero folder on my com puter. but how do i acess the zoteropreference when it's saying "There was an error starting Zotero" after cliking on the zotero button on the lower right corner or from the tool menu ?
Though probably you just want to go to about:config in the Firefox address bar, search for dataDir, control-click, and reset each one that pertains to Zotero. Then restart Firefox and Zotero will be using the default data directory.
B.
Is this a normal hard drive or an external drive? Are you accessing the same folder from somewhere else (network share, Parallels, etc.)? Is there a zotero.sqlite-journal file in the directory when Firefox is closed? (If so, delete it.) [Edit for posterity: Don't do this. It could result in database corruption, and if it helped it'd be due to some other root cause that needed to be fixed.]
Otherwise, we can't really help you with this—if Zotero can't write to the database it simply can't work.
When in ran into the problem, i simply unistalled zotero and then reintalled it ... (if that help). but it didn't fix the problem.
In the event i can't do anything about it, how can i recover my database and reintall the all thing ?
You can always copy the data directory to a local disk and point Zotero at it from the Advanced pane of the Zotero prefs.
I copied the zotero folder on my com puter. but how do i acess the zoteropreference when it's saying "There was an error starting Zotero" after cliking on the zotero button on the lower right corner or from the tool menu ?
I guess to recover my library i should copy Zotero.sqlite into the default zotero folder ?