Source: dolfin Followup-For: Bug #973767 Yeah, I'm more certain SLEPc is the problem. In the new release they abolishing SLEPc.pc, renaming it slepc.pc. Since pkg-config is case-sensitive, the unexpected change is causing problems.
Notice how the reported error is only with dolfin64. Because the proper SLEPc is not detected, the 64-bit build is mixing up 32-bit and 64-bit builds of PETSc and SLEPc. Resolution in progress.