Go ino C: >>> Feralheart >> Media > particles and delete any ending in a _0, _1, and so on.
Also try this:
How to Change Your Rendering System
~Windows 7 and 8~
Method number 1~
First, go into C: > Feralheart. If you look at the FH main folder, you will see a flie called:
'orge.cfg'
Click it, and open it with 'NOTEPAD'.

Look at the first two lines in the orge.cfg file. That is where you change your rendering system.

If you followed everything that was typed and the instructions in the pictures, you should have successfully switched your rendering system.
Method number 2~
Turn on FH!
On the main screen, you will see this:

Click options, and go to video. Click 'Rendering System.'

Then just simply switch your rendering system.
Note that sometimes method 2 doesn't always work- That's why I listed the orge.cfg file first. ^^
Good luck! Hope this helped those who don't know how to change their rendering system!~
Also, have you exported this map before? And make sure all the items in your map are in new object groups.
If none of this works, save presets, maps, etc somewhere other then you FH folder an unnstall. Then reinstall.
Good luck!