Check the WIND file in all mapsets and DEFAULT_WIND in PERMANENT.
There should be fields which say:
proj: 3
zone: 0
It sounds as if the "proj" field is missing (perhaps others as
well). Here is a WIND file that you can put there:
proj: 3
zone: 0
north: 90n
south: 90s
east: 180e
west: 180w
cols: 360
rows: 180
Michael