Ponycoin is forked and modified from Bitcoin v0.8.0, an old release that still has the miner in it, so it most likely detects as the BitCoinMiner virus.
This is a complete waste of time since it doesn't even work, seriously why bother releasing it if you didn't even test it ?
Meh, I might as well remake Ponycoin from v0.11.0 and see where I get, and I'll update this post when ready. v0.8.0 is just way too old now, so might as well give it a shot.
I pretty much only tested this on my dev PC with an Ubuntu VM and Windows 7, so I expected it to go rough at first.