Incompatible ELFs?

I’ve noticed that some of the ARM ELF executables I get from other places, or some that I build with OpenEmbedded cross-compiler tools, will not execute on BBB Angstrom (giving the supremely unhelpful “so such file or directory” error). The working binaries on the BBB have the ELF header flags word set to 0x5000002, indicating EABI version 5, no specified float format (defaulting to soft floats, I believe?). The one’s I get that don’t run have flags set to 0x202, old ABI, soft float. Is there a good reason why the newer kernel can’t run the older binaries? Are the ABIs that different? Is there something else causing this incompatibility?

It's not the "kernel" its the lack of the linker/libraries in your
user-space.

Regards,