Hi,
Ignore the alternator warning lamp for the time being...characteristic of the Beta!
Open Circuit...yep you got it, a broken wire, a blown bulb, or component failure.
If we assume that all bulbs are healthy, and the earth return from these bulbs are healthy, and we know that the flasher unit is receiving a signal from the stalk switch. Our attention must focus on the flasher unit or the hazard switch or wherever the right hand circuit starts it's life. Does the hazard switch work the right hand lights? I'll have a look at the diagram tomorrow to gain some info.
John.