Clean the contacts of the jacks on the preamp and the plugs of the interconnect and that will most likely fix the problem. Use 99% Isopropyl alcohol, contact cleaner, DeOxit, something like that. I bet that does it.
But to answer your questions- You may be able to successfully run the mics directly in, but best performance will be achieved via the preamp, which will both power the mics properly by providing something like ~8V bias voltage instead of ~2.5V (< guessing on the R07's PIP voltage) as well as providing good needed gain with a low noise floor. If bypassing using the preamp you will probably need to use more input gain on the R07 to achieve the same recording levels, unless you have the gain of the CA-UGLY dialed way down to unity (no gain, only acting as buffer and providing bias voltage) which is possible. The lower bias voltage will decrease max SPL handling (loud stuff will distort more easily) and might increase noise somewhat.