[support] whoops! Changed settings.php and now get redirected to "Database Configuration" page.

I'm having one of those dreaded "can't get into my own site" moments!

I altered the cookie lifetime in settings.php from 2000000 to 900, opened ftp, uploaded

.....and now I get redirected to this URL every time:

http://www.mysite.com/install.php?profile=default

looking on the drupal.org forum, it seems as though permissions may be my problem. At the moment, it is 644. I just made a comparison between my settings.php and the currently settings.php in the 5.1 tar and the only difference is the cookie length, so I'm stumped.

I don't want to enter any db info on the db config page lest it start to do fresh install. I have backed up db just in case.

anyone had this problem?