Cause: A host language program attempted to open too many cursors. The initialization parameter OPEN_CURSORS determines the maximum number of cursors per user.
Action: Modify the program to use fewer cursors. If this error occurs often, shut down Oracle, increase the value of OPEN_CURSORS, and then restart Oracle.
ALTER SYSTEM SET open_cursors = 400 SCOPE=BOTH;
Try to find out application to see why cursors are staying open.