I'd like to nominate myself as the MODX muppet of the month after unsuccessfully chasing down a getResources problem for the last 6 hours only to discover
I was calling
<img src="[[+tv.thumbnail]]">
instead of
<img src="[[+tv.Thumbnail]]">
If you can't see the issue there, you could be next month's MODX muppet
During that time, I had done several reinstalls, been on forums, swapped TVs, changed templates, made test TVs, banged heads etc etc. Don't let it happen to you!