Pops and Clicks

I use a PC with cubase 6.6.5. I work only in midi, and when I export in anything other than realtime, I get tiny little pops and clicks at 20s, 26s and 30s (please listen to attached file)

http://harrywaters.co.uk/orbitpops.html

This happens on ALL mixdowns at various places, but is always in the same place each time I try to mixdown each particular tune.

I use windows 8 64bit.
i7-4770 3.4GHz
32 GB ram

I have a Focusrite Scarlett 18i8 (midi interface) with latencies of 3.3 and 4.3s in/out.

I use Play as my VST:

I’m of the opinion that I have more than enough CPU and ram to be able to do non realtime mixdowns without these clicks. Please could someone tell me what I’m doing wrong ?!

Any tips would be greatly appreciated.
Thanks

I don’t hear any clicks or plops, not in this topic nor in the other topic with the same subject. No need for clutter here, really: Audio Mixdown pops and clicks - Cubase - Steinberg Forums