Manifold error

Could someone please help me figure out what exactly is non-manifold about my design? I've been using Sketchup, exporting as a Collada file, and everything (even much more complex shapes) have turned out fine.

Anyone wanna help me?

I've uploaded a Sketchup file as well as a Collada file if anyone needs them

Thanks!

Hi here's your corrected file, the problem you had was the small cylinder coming out of the block was not attached.
Let me know how you get on?

Regards
V

http://www.dotsan.com

Thanks a lot, VirtualV. The new part worked a treat.

I'll be sure to credit you in the description.

Thanks again,

A1

EDIT: Forgot to mention, i've now finished all the 'Magnen' parts necessary to then hopefully build a robot that turns into a magnet, based completely off of this picture (with some tweaks to allow for my very basic CAD skills): http://yugioh.wikia.com/wiki/Morphtronic_Magnen Thanks for your help.