After downloading the game i tried to run the installer but it said that the source file is corrupted you should run the installer intergety check or sonething
I am on windows 7 and tried to run the installer as admin
Please help :(

Sounds stupid, but... maybe the source file is corrupted and you should run an integrity check!?

I've had this happen with a GoG download once because they didn't name the files in the package correctly. Check the files and make sure the names match up.

You mean the setup and the bin files names?

Yeah, I had an offline installer that I downloaded where the setup and the bin file names didn't match up and it kept failing as described. Renaming the files to match fixed it.

The proplem is that I dont know what do they mean with the "source file" nor how to run the check, oh and its not stupid thanks for trying to help me :) I will try this tomorrow and report back, thx for the tip!

Make sure all the files are the same name, they are all in the same directory, and that they have fully downloaded.

Just tried it, didnt work :( I am sure of all of this yet it still doesnt work

So you downloaded the files via browser, and the fully downloaded, I.e. Browser told you they completed, all of them, and it didn't rename the files or anything? If so I would contact support.

I will check my installers when I get home if you like for file size/version and update history. Possibly they have pushed a new update or some which has broken the files.

i thought for a second that title is fallout new vegas ultimate installer error.. :-/

Did you check the files sizes are right? Or did you try to redownload it again?