Problems while creating new document

I’m having problems while trying to create new document.

I’m filling up Title, Description etc. and after that when pressing SAVE I see the progressbar for very long time and nothing happends - only the progressbar is running
over and over againg.

I’m refreshing the page after little while and I have to start over again with adding a document. Any clues?

Before we can help:

Note: If you’re posting about a bug, please state all of your Environment information in your post: Version of MODx, Traditional or Advanced distribution (for Revo), Server OS, Server Version, PHP Version, MySQL Version (client and server), is pdo_mysql installed, your Browser type and version, if you are using any opcode caching such as eAccelerator, APC, winCache, xCache, etc; any relevant errors in core/cache/logs/error.log, and any other environment data we should know. We can’t help you without that information.

Also, what version of Revo.