I encountered this error after someone had left unfinished a failed attempt to setup ServerA as Publisher using the existing Distributor on ServerB. When I tried to run SQL2000 E/M's "Configure Publishing and Distribution" wizard on ServerA, I got this error. SSMS has separate wizards for Configuring Publishing vs Configuring Distribution, and one of those offered to drop a hidden existing (broken) Publisher partially-defined in metadata on ServerA. The wizard executed sp_dropdistributor @no_checks = 1, @ignore_distributor = 1, and the error 18483 was resolved for all client tools. I surmise a wizard had neglected in the past to create and coordinate the distributor_admin accounts & passwords between ServerA and ServerB; I never found that account on either, and it is apparently required if Publisher and Distributor are on different boxes (or instances?).