Solution to the issue

It ended up with my gamefiles being corrupt and needed to download a new client. But before resolving to that, there was a serial of steps there should be tried first.

• Check that you're running the installer as admin, and that it has permission to write files in the place you're installing the game. It is possible that it is trying to put a file somewhere in the same folder or in the Documents/My games folder, and is unable to.
• It may also be worthwhile to note that some users have reported overcoming this issue by adding the Installer Application to their Windows Firewall Exceptions. (same apply for other firewall programs)

Note: There are several files you need to make sure are covered by these rules. Client.exe, PathOfExile.exe, and CrashUpload.exe. All found in your game folder.

If that does not work, then move on to trying to fix the files manual.

• Open your internet browser and enter the link displayed in the crash window - patchxxx.pathofexile.com:8095/patch/x.xx.x.x/CrashUpload.exe (the "x" are the patch number shown in the error msg)
• Download that and save it and then copy/paste it into the game directory. Once that is done you might still get a game crash when the game says "connecting"
• If this is the case go into the games directory and delete the client.exe file and then rename the file client.tmp to client.exe

When I did it, it kept sending me a new error, with a different number. After a bunch of different numbers, it returned to the first one and started over. At this point I was told that my gamefiles has been corrupted and needed a new install.

I hope this can help someone else, if they happen to get the same error. Furthermore, do not hesitate contacting support at [email protected]. I wrote to them a late Saturday evening (CET) and got a reply within 30 mins. Each following mail in the troubleshooting where less than 20 mins between. They react really fast and provide good solid, accurate support.

Personal I'm more tempted to invest in a supporter pack, after this experience.