ok, so ive downloaded a lot of parks from nedesigns but some of them are an sv4 file which wont open in rct2

Anyone know whats up??

Yeah thats because an SV4 file is a Saved Game from RCT1. RCT2 Saved Games end in SV6

Yeah i thought about that, is there anyway of converting them to sv6?

Not in the way you want to see them.

But you can pull the landscape into the scenario editor. Unfortunately, you lose all the different 'walls' this way. I'm not sure if you even get to keep some of the other scenery objects that you are able to place in the game or not.

In RCT3 you can actually convert RCT1 and RCT2 saved games into RCT3 files.