We ended up buying POE injectors for the phones having problems.
We recently deployed N2048p switches in our building to replace our aging Cisco 3750G switches and ran into some problems with POE.  We have some devices that work perfectly fine with the Cisco switch but will not power on with the Dell switches.  Most of the devices in question are AAstra 6725IP phones, and about a third of them won't power on at all.  The N2048 shows "test-fail" on the status column with a "show power inline".  We are on the latest firmware 6.2.0.5 and the latest firmware on the phones.  This is also affecting our building access system as it runs off of POE as well.  I've contacted AAstra, but so far they have been little help.  Anyone else had the same experience?
POE issues with N2048P