Otherwise unattested, whether as a toponym or anything else. (The entry, incidentally, is out of alphabetical order here, but Adler notes that ms G positions it appropriately.)
NF: perhaps an error for Hyampolis, in central Greece (upsilon 8).
DW: I find NF's suggestion unconvincing, but it is hard to think of a better one. (Present-day Pampole, in Guinea, is plainly of no relevance.) Conceivably some connection, with pampolis, the transmitted reading -- disliked by modern editors -- in Sophocles, Antigone 614.