From Skype forums: http://community.skype.com/t5/Windows-desktop-client/Can-t-type-anything-if-i-m-in-a-video-game/td-p/3926041
Starting from 2 months ago aproximately, whenever running games detectable by Raptr on the 64-bit client causes any other parallel application in 32-bit to become very unresponsive, notably web browsers and VOIP apps such as Skype. I'm personally on Windows 7.
The workaround for this problem are:
1- Running the game on the 32-bit app. This is not really desirable since most games are much more resource-intensive running as 32-bit instead of 64-bit.
2- Running the 32-bit apps in compatibility mode. This is a bother to do since apps that run on startup won't work anymore unless you deactivate UAC or perform a workaround with Microsoft's Compatibility Administrator which involves even more work and troubleshooting. Using compatibility mode also utilizes more resources, so even if Skype already doesn't use much CPU if you are running a low end PC it'll probably impact your gameplay.
3- Close Raptr completely. I found this option to be by far the easiest and most desirable.
I have gone ahead and created a ticket regarding this issue so that we can look deeper into this. Ticket #12132 for your reference. Additionally, I will be locking this thread so that we can funnel the answers into the ticket. Thanks for writing in this issue so we can be made aware!