Enterprise Information Systems (EIS) have become the core information processing architecture of large businesses. This study examines the role of Knowledge Social Networks (KSN) in facilitating EIS-related knowledge acquisition accounting for the domain expertise of knowledge sources, its interplay with user task complexity, and their impact on EIS implementation. While research on KSNs has considered knowledge relationship ties, both for knowledge acquisition and dissemination, and their impact on knowledge outcomes and employee performance, it has not addressed the domain expertise of knowledge sources within KSNs and the quality of resultant knowledge flows. Data for the study was collected six months after the implementation of an Enterprise Resource Planning system. Preliminary results indicate that while knowledge acquisition through KSNs is important, the task complexity of users and domain expertise of knowledge sources need to be considered, especially for users dealing with complex business problems.