Apple has released iTunes 11.0.5 for Windows and Mac that includes fixes for an issue with iTunes in the Cloud, where some purchases may download or play unexpected items.
You can download iTunes 11.0.5 via Software Update or through direct links below. iTunes 11.0.5 is also available for 64-bit Windows.
Download iTunes 11.0.6 for Windows 64
Download iTunes 11.0.6 for Windows
Download iTunes 11.0.6 for Mac