Sometimes with bugs it helps to reinstall or do a cold start.
Sent from my iPhone
Restarting CH is definitely worthwhile (as Sharron said). Feel free to try the following before reinstalling, but a reinstall has fixed problems for a few people too.)
Here is a simple "legs" puppet I was using. (Its just legs - I have not drawn whole character in side profile!). If you download, "import" into a demo project, create a new scene with just this puppet in it, does left/right arrows work?
Helen Legs.puppet - Google Drive
If you cannot work it out from there, feel free to export your puppet, upload to Google Drive/Dropbox/etc and share a public link then post it here in the forums or send me a direct message. I don't mind having a quick look to see if I can spot it (or if it works on my computer).
(This is how I used the legs - I set Scale X to -100% so to run the other direction - too lazy to get the profiles going right, plus with only one profile I can make it walk backwards which seemed possibly useful.)

Here is what I did and a quick run through of puppet as well. Note, I did not use any profiles, but that is probably not important for why arrow keys not working for you (I am guessing...)
Helen legs demo - YouTube