There is already an open DataReader associated with this Command which must be closed first

Every so often in our ASP.Net website we would get the error, "There is already an open DataReader associated with this Command which must be closed first" referring to a SqlDataReader.  We would tweak code here and there and get it to go away.  Later another code tweak would bring it back.  We have no idea what is causing it.  

It is in a block of code that creates a SQLCommand, creates a SQLDataReader, and destroys the SQLDataReader and SQLCommand.  We are not sure how it is possible that another reader is executing on that command.

As a work around until we can find the issue we have added this attribute

MultipleActiveResultSets=True

to our connection string and it has seemed to have bypassed the problem.  I know it likely causes other problems, but due to the environment we work it that's what we have to do.