I have just encountered this error for the first time since i started using AE about 6 years ago.
I am running a PC (windows 7 pro), i5 2.90GHz 64-bit OS, 16GB RAM, and 1 GB Graphics card, dedicated 1TB HDD for Cache. Creative Cloud subscription.
I had no problems up until the update to 'After Effects CC 2014', since this update i cannot generate a RAM preview. I have read countless forums and i have followed previously suggested solutions (purge, remove VCReflect plugin, started AE as administrator etc), to no avail.
Any suggestions will be welcomed.
My anti virus was blocking access to Adobe Dynamic Link.