This has has happened to me before. Probably due to one of the recent plugins you tried to install was not compatible with your version of elgg, think back on which one(s) they were, and go to your FTP and delete the folder in the MOD folder for that plugin, then the admin section should show up. Make sure you try to add plugins that will work correctly w/ your version of elgg, or try re-upload the plugin -- its possible files were corrupt. You may also want to click on the upgrade button from your dashboard once the plugins were removed from the MOD folder so elgg still isn't looking for the data.

Thanks I solved this one.