If this is not the correct place for this question, let me know and I will move it.

In the past few days, I have had several SETI runs terminated very early with the following result coding:

Work Unit Info
True angle range: 0.393911
SETI@Home Informational message -9 result_overflow
NOTE: The number of results detected exceeds the storage space allocated.

True angle range figure changes.

What does this mean? Is this a "Divide by zero" kind of thing?

No this is not a "Divide by zero" kind of thing

This error means that the found signals exceed the maximum signals reported threshold for that Work Unit (usually this threshold is 30 signals). This error is not serious and happens often when there was much radio interference while the Work unit was taken.

***EDIT***
Renamed & moved your topicto the projects forum, because it concerns a particular project and not BOINC itself.

If it appers sometimes, it would be a noicy signal, and is OK.
But if you get this error on every result, it could also be a problem with the software (porting problems for example) or with the hardware.