To help us investigate, can you please tell us the following details:
1) Which build of MetaTrader 4 are you using?
2) What is the full path of the MetaTrader 4 installation folder?
3) Do you see any error messages that could help us investigate?
1) MetaTrader 4 Build 509 (works when I changed the installation folder);
2) “C:Program Files (x86)MT4 ECN FXOpen – Backtests”; and
3) The program only says that the installation folder is invalid, it does not contain a valid version of MT4, however I have installed on another computer the same version of MT4 but with the default installation folder.
Make sure you have launched your MT4 at least once before trying to select the folder. Tickstory looks for specific files to be present before it recognises the MT4 directory as being valid.
Check this post for further information to see if it assists: