This error can be caused by various things. Errors you might see are "System Resource Exceeded" and "Not Enough Storage Is Available to Complete This Operation." You should see the following KB articles to see if any of these situations apply to your problem:
KB #248668 - BUG: "Not Enough Storage Is Available to Complete This Operation" with Oracle OLE DB
KB #189782 - BUG: RegQueryValueEx() Fails When lpValueName Is NULL
KB #182423 - FIX: "Not Enough Storage is Available..." Error with ADO
KB #174776 - Index Server Queries Return Not Enough Storage Is Available Error
KB #254759 - BUG: ListAvailableServers Method of the SQLDMO.Application Object Causes Error 0x800A000E
Otherwise, a sure way to alleviate the problem is to upgrade or reinstall the latest version of MDAC (
MDAC Download Page).