Crystal Reports run-time error – “Failed to open a rowset”

Details: HY000:[Microsoft][SQL Server Native Client 10.0]Connection is busy with results for another comand

SOLVED
Report ran in Crystal Reports designer. Problem turned out to be that there was an unlinked table in Visual designer. Replaced the fields from this table with fields in a view, then removed this table from the report and report then ran

USED this entry:
SRS 18th Dec 2012

THIS ERROR Can also be if there are truly multiple start points for your Crystal Report

In this case use two connections.  This could be the same ODBC connection added to the report again. This works as proved 11-Jan-13
See Purchasing\Requirements.rpt