CIL Fails with with no errors/messages

When I run CIL compilation on a customer, it just stops with no errors.
The environment has two AOS servers, and the version number is 6.3.2000.326

I tried the following steps with no luck.

1. Stopped the two AOS servers.
2. Deleted CIL-files on both AOS Servers.
3. Start AOS1
4. Run Full CIL compile.

That did not work, the CIL compile simply stopped with no messages.
Then I did the following.

1. Stopped the two AOS servers.
2. Deleted CIL-files on both AOS Servers.
3. Start AOS1
4. Run full code compile.
5. Run full CIL compile
6. Run Incremental CIL

There was no compile errors from the normal compile, and the CIL still just stops with no errors.

Any idea what the problem might be?