I don't have a bulb cable, and when I do an exposure longer than 30 seconds, MaxIm appears to freeze/hang

If you don't have a bulb cable attached to the computer and you expose over 1 second (in the 1 second mode) or 30 seconds (in the > 30 mode) then the computer will wait for the bulb to take effect (but it won't since the cable is not there) and the software will wait. You can clear this situation by clicking the shutter by hand and the exposure will happen.