Don’t paste content into WP from other applications (such as Word). Try sorting out some of the validation and CSS errors on the site.
On the Mystique theme in my widgets I try to drag and drop a text box onto my sidebar and it will not do it. It will go to the top of the page and nothing happens.
Have you tried:
– deactivating all plugins to see if this resolves the problem? If this works, re-activate the plugins one by one until you find the problematic plugin(s).
– resetting the plugins folder by FTP or phpMyAdmin? Sometimes, an apparently inactive plugin can still cause problems.