SQLbackup application closed when I hit ok on message

when I open redgate sql backup 5.0, i m getting following message and when i hit ok. it just closed redgate backup. why?

please help me.

SQLBackup v5

The database disk image is malformed
database disk image is malformed
WorkerExecutionException

at RedGate.SQLBackup.Engine.ConfigurableThreadPool._1(Exception )
at RedGate.SQLBackup.Engine.ConfigurableThreadPool._1._2()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

---

SQLiteException

The database disk image is malformed
database disk image is malformed

at System.Data.SQLite.SQLite3.Reset(SQLiteStatement stmt)
at System.Data.SQLite.SQLite3.Step(SQLiteStatement stmt)
at System.Data.SQLite.SQLiteCommand.ExecuteNonQuery()
at _6._5(Server )
at _6._2(Object )

Thanks
HELP!!!!!!!!!!!!!!