When trying to play a movie I purchased from Google Play, the movie player (same Flash-based one used by YouTube) spits out the following error message over a background of faux-TV-static:
An Error Occurred. Please Try Again Later.
This is super-frustrating because I had just paid REAL money ($3.99) to watch the movie, as opposed to, you know, going someplace illicit to download it for free.
All other YouTube videos play fine for me, including the freaking Google Play trailer for the movie I bought! Sheesh. I Googled around for solutions, but I guess Google Play is too cutting edge for Ubuntu, because most of the solutions (in Ubuntu Forums, for example) recommended installing a Linux-specific Firefox plugin called Flash-Aid that essentially runs a configurable set of shell commands to ensure that you have the latest Flash from Adobe installed, and that you do not have any of the possibly conflicting free implementations of Flash installed (Gnash, etc). Suffice it to say, installing and running Flash-Aid did not help.
Also, I would add, I experienced the same error message trying to play the movie in Chromium.