Wrong Syllogism

Just random thoughts... Note the statements: 1. One who is omniscient knows everything. 2. One who is omniscient has nothing he or she does not know. 3. Knowing everything means to know what you don't know. Now, if you combine the statements 1 and 3, you have statement 4: 4. One who is omniscient knows whatever he or she does not know. Statement 4 makes sense. However, statement 2 implies statement 5: 5. Nothing is whatever one who is omniscient does not know. Statement 5 still makes sense. Now, if you combine statements 4 and 5, we finally have statement 6: 6. One who is omniscient knows nothing. Hehe. What's wrong with this? =))