I looked that over, and noticed some things that could be done more simply, and what seemed like some shortcomings, and came up with the attached RotateLinesAbsAng.lsp and its RLAA command. Aside from being shorter, some of the functional differences are:
Lines on locked Layers can be filtered out during selection, reporting on any that it finds in the selection process, rather than trying to rotate them, counting up the errors that result from those on locked Layers, and reporting the count of those afterwards.
Theirs asks for the angle after selection in the pre-selected-items [noun-verb] mode [obviously], but before selection in the verb-noun mode. Mine asks for it after selection in both cases, which is also more analagous to the way regular Rotate works.
In noun-verb mode, theirs keeps all pre-selected items highlighted, even those that are not Lines or are on locked Layers and therefore won't be rotated, while asking for the angle. In verb-noun mode, it highlights even Lines that are on locked Layers during selection. Mine shows only the Lines that will be rotated highlighted, in both modes.
If you type U after using theirs, it doesn't undo just what that command did, but goes back past that to undo whatever previous command you did! Using U after mine undoes its own operations only.