Try uninstalling and reinstalling to see if that fixes it. If it doesn't Check-In to your profile, select the 757. Select Extended Download Service then select the Get New Links button. Download it again from the new link and install it to see if that fixes your problem.

I say this because I had a weird problem with my 757-300 Expansion Model v4.4, it appeared to install properly but I had problems with it not working properly. After downloading it again and installing it it has worked fine ever since. It's worth a try.

Hope this helps

Mark