I found a better solution on the Chrome product forums by a user called Gary. The original thread is here.
Navigate to C:\Windows\System32\GroupPolicy
Open each subdirectory there and change the *.pol files to *.sav, E.g. registry.pol becomes registry.sav.
Hit Windows-Key + R, type the following in the box and hit enter
reg delete HKEY_LOCAL_MACHINE\SOFTWARE\Google\Chrome
In the command promt window that opens type: Yes and press Enter.
Restart Google Chrome and check whether you can change the search engine.