'Name Collision: index.html' for 'Qt 5.1.0 Reference Documentation'

PACKAGE VERSION:
qt-linux-commercial-5.1.0-beta1-x86_64-ubuntu1110-offline-2013-04-30-31.run

STEPS TO REPRODUCTION:
1. Install Qt SDK on Ubuntu 12.04 64 bit.
2. Run Qt Creator.
3. Go to Help mode (CTRL+7).
4. LeftClick on 'Qt 5.1.0 Reference Documentation'.

ACTUAL RESULT:
The following error is displayed:
-----------------
Name Collision: index.html
-----------------

EXPECTED RESULT:

■No error.
■Proper documentation should be shown.