In case of this error message:.

Error-200, Message: HTTP Error

• Open wp-config.php in your sites main directory via FTP (or cPanel)
• Scroll to the line which reads/* That’s all, stop editing! Happy blogging. */
• Add the codeset_time_limit(60);above the line/* That’s all, stop editing! Happy blogging. */text

Set the set_time_limit(300);

Some hosting companies may not allow you to overwrite this setting from wp-config. However, you can still try.

Here is a list of other common limits you can check and set to max possible (if your server allows it)

Copy from here: http://wordpress.mcdspot.com/2012/03/20/ways-to-increase-max-file-upload-size-and-execution-time/