[galaxy-dev] Problem in uploading file

Hello everyone, I had configured galaxy with MySQL database and for some time it was working fine. But suddenly it started showing following warning whenever I start galaxy. ".../galaxy-dist/eggs/SQLAlchemy-0.7.9-py2.6-linux-x86_64-ucs2.egg/sqlalchemy/sql/expression.py:1927: SAWarning: The IN-predicate on "request_type.id" was invoked with an empty sequence. This results in a contradiction, which nonetheless can be expensive to evaluate. Consider alternative strategies for improved performance." And now I am not able to upload any file. Please help me to resolve it. Thanks