Adobe Flex RSL Error in IE

This is another case which I know the cause and the solution for a problem. But I don't understand why it would cause a problem.

Environment:
  - IE10, Win7, Flash Player 11.8 debugger
  - Google Chrome  28.0 with Flash Player 11.8

Symptom:
  Flex application stopped  working in IE. Always getting this error message: "RSL Error 1 of 2". RSL is short for Runtime Shared Library. Using ServiceCapture, I do see the main SWF loaded, and the first RSL loaded, but no the rest.
  The same Flex application works perfectly in Google Chrome.

Cause:
  In the the IE Security setting, "Enable Protected Mode" is unchecked.


Solution:
  Go to IE > Tools > Internet Options > Security, make sure "Enable Protected Mode" is checked. Then restart IE. Voila, it all works again. In retrospect, I might turned it off when I was trying to set up Selenium test framework.

Question:
  It's still beyond me why "Protected Mode" seems to make IE 10 more compatible. Just a few days back I had another problem with Office Web application due to the exact same cause. An extra IE windows will always popup when I open an Office 2013 application in Excel. The problem is gone after I enabled protected mode.

----
Flex: a RIA web application development framework based on Adobe Flash technology

Modem Error: NO CARRIER

What to check when you get "NO CARRIER" (numeric code: 3) error from Modem:

• Verify Modem is connected to phone line properly;
• Verify the phone number you are dialing works properly by calling this number using your phone, and verify that you hear: first ring tone, then the negotiation tone (yes, you should be able to hear the chirping sound over a regular phone);

If you can hear the negotiation tone, but frequently get "NO CARRIER" error, here is a solution:

Set modem register S7 to a longer timeout value. 50 is the default, you can set it to 120 (ATS7=120). Sometimes, you can set this timeout value through MODEM configuration GUI, you can find something like: "Cancel the call if not connected within __ seconds".