According to this Reddit response by Booor, this happens when somehow you get two flash players enabled at the same time. To fix it, simply disable one of them:
- Go to chrome://plugins
- Click on "+ Details" on the right top corner
- Find the flash player plugin and disable one of the DLLs
The DLL to be disabled should be the one that's not on the Chrome's folder, but I had the same problem, and disabling the external one didn't help, however, it worked when I disabled the internal one and enabled the external DLL.
I tried this fix and worked for me, and I noticed that the internal version that was problematic was version 13.0.0.214, while the external one that works is the 12.0.0.70. I don't know if this is relevant, but version 13.X may be the problem here.