No, that doesn't prevent the report to be loaded... it is just an annoying false error.
If you check the other discussion http://community.qlik.com/message/225940#225940 you can see that the problem has been solved with patch 11291.
Still, in those cases where a report really fails to load an extension, it would be interesting if the logs show both doc and expension names.
A patch has been created to fix this issue please contact support it is is patch 11291. Here is a list of other issues it resolves:
Bug 46467: AJAX: actions don't work in text boxes when accessing the qvw from an iPad
Bug 46817: QV11 SR1 chart error on Extensions: Failed to load extension. Make sure it is available at the correct location
Bug 45376: Web Parts - Green Colour - CSS creating Automatically
Bug 46050: Conditional Expression are slower as same Expression with if statement
Accumulated bugs fixed since 11.00 build 11282 (SR1 - Update 1)
Task 44841: Implement hooks to display QVW-file in QMC
Bug 46699: Publisher - Task set up to trigger on Multiple Events Completed does not work
Bug 42972: QV Destop: Errormsg 'There was a problem sending the command to the program.' when opening QV doc without license.
Bug 45425: OEM Embedded License not working (OBS! This is not OEM Island)
Bug 46971: Exporting excel as numbers does not work fully