My module action menus have stopped working.  When I hover over one of the triangles, the triangle turns into a spinning wheel and the menu does not appear.  The problem began as soon as I upgraded from 5.6 to 5.6.1.  Any help in dealing with this issue would be much appreciated!

In IE, I noticed a message like "Error on page" in the lower left corner of the page (on the status bar), so I enabled "Display a notification of every script error."  Once I did that, the details, when I hover over a module menu triangle, say
"Message: Sys.ArgumentException: Cannot deserialize empty string.
Parameter name: data
Line: 5
Char: 50445
Code: 0
URI: http://www.3rddayarts.com/ScriptResource.axd?d=(167 more characters)"
where "(167 more characters)" is a mixture of letters, numerals, and a few special characters ("-", "=", "&").

Any tips on how to fix or work around this error?

Mr. Atalay,

Solutions? Not for me, yet.

Suggestions? Try here:
http://www.dotnetnuke.com/tabid/795/forumid/108/postid/404459/scope/posts/default.aspx#404459

I'm having a different problem w/ 5.6.0 that 5.6.1 fixes, so I really need to get this fixed! I would be very grateful for any help I can get!

I have debug the calls from client to server and I have see that the response (after the post, after the mouse hover) in json format is not completed.
The problem is in the GZip compression. I have disable this, and now works.

Try this, and write ;-)

I hope that the team resolve this because is not a little problem.