Setting up trusts

I am trying to setup a trust between 2 domains on different subnets. The trusts never verify. My network is setup similar to the following:
DomainA PDC 10.0.1.2
DomainB PDC 10.0.2.1
DomainC PDC 10.0.1.1
I can setup a trust between DomainA and DomainC, but not between DomainB and DomainA or DomainC.

Any ideas?