That version (3.3.7.2) is no longer available, and has been replaced by 3.3.7.3, 3.3.8.2, and the latest version v3.3.9.1. The latest version v3.3.9.1 is recommended for that switch. [URL] Note: further down on the page is a dropdown to see the previous versions. Since the version listed in the computability matrix is no longer available you can use any version newer than the version listed and it is expected to continue to work as tested, and will be supported. -joe 
This may not be the best place for it but i wasn't sure whether storage or equallogic would be able to answer this. In the latest equallogic compatibility list for the ps4100xv and powerconnect 6224 switches the matrix says to use firmware 3.3.7.2 for the switches but I can't find it.
Equallogic compatibility