When executing on connection to Oracle "an INTO clause is expected in this SELECT statement"

I have an Oracle database that - when I connect to it and execute even the simplest "Select * from myTable" statement - returns:
"ORA-06550: line 1, column 7: PLS-00428: an INTO clause is expected in this SELECT statement"

Connection string is fine, connection is established and opened with no problems, only when for example calling executeReader on a OracleCommand object, I get the above error.

Any ideas?

J. Jespersen