I recently had an issue in SCCM which had me stumped where an application would not deploy to a remote site, it would show in Software Centre and on the "Installation Status" screen would get stuck at downloading 0% and not progress from here. What was strange was that there were task sequence which would install fine on the same site. The fix to this issue was that I had realised a new DHCP scope had been added but the new boundary group had not been setup correctly. I followed the steps of setting up a boundary with the IP range, adding this to the existing boundary group. After about 30 minutes the application started pushing down to all the clients.