So,i was having a problem just now and was able to fix this problem. I was also browsing the internet for possible solutions and there was no definite answer or it wasn't highlighted because there wasn't the word fix in it.

so basically this is how I solved my problem. It's super easy.

Thing you need to know.
1. I have WinRar installed
2. I have 7zip installed


So initially, when I get a copy of a PS2 game, it is saved as (filename).7z. What I did before was unzip it and saved it to another folder. WRONG! Don't do this. This is the cause of the error "File not found. Path: IsoFileSystem".

So what to do?

Instead of unzipping using WinRar, Right click the file, click 7zip, click Open archive. A new dialog box would open and you would see that it is (filename).iso file. That's the solution! Just extract the .iso file and run it on your emu.

Your Welcome!