I've got a watch folder set up to convert Lossless Animation codec files to H.264 (1280x720, 1 pass, 5 target 8 max, 3.2 level; 44100Hz, 128 kbps). I had a batch of 300+ videos going, but the error appeared within the first 30 or so twice. Clicking continue made it go away with little observed issue, but the error pauses any encoding so if I have a batch of X hundred videos going overnight, it might only do so many of them before the error arises.
Sorry I don't have a screen shot, but this is what it gave me.
adobe media encoder has encountered an error exporterparam.cpp-509
edit - Windows 10, CC2015. i7 5960x, 64 GB corsair memory, GTX 970. Watch folder is on a SM951 SSD and hasn't had an issue on 50+ encodes since I got the disk.