I was trying to fix an issue with imagehandler but now cannot log in to admin.

In fact I just get a blank page and no log happening. I have checked config and this is as was exactly same as the front end in terms of the server path.

If I change the server path then I get the install page come up telling me either to install or correct my config. I have just down loaded the live site which works fine to get rid of any changes to files that I made locally as they are an exact copy after every change/ update going live. So this should have got rid of any errors on any other files and therefore just the config file differs.

I do not get any error messages or logs. database user and password are correct as it works for the front end.

What can I do to help debug this? It there any other way of turning on tracking where the programme gets to before it stops and decides not to bring up admin login.?