The line
orbit = KerrGeoOrbit[0.532, 1532, 0, .7`32]
Produces the error:
"FindRoot: The precision of the argument function ... is less than WorkingPrecision
(30.999999999999996`)."
where the ... is the full expression for IBSOPoly in SpecialOrbits.m
This does not happen for all pairs of a and x, but when it does occur the following small change should fix it in most cases.
The FindRoot is in KerrGeoIBSO where the WorkingPrecision is prec - 1 (e.g. 31 in the example above). Changing this to prec -1.1 or prec - 2 should solve the issue.