The response about having tried to download 2012 SP1 and getting that error message about it failing is really the more useful information here.
You said you are trying to work over the school's network. It is certainly possible that they have network settings preventing you from getting the downloads you need. Whether it is based on type of file to download, source, or a general prohibition on preventing someone from installing software on a PC if they aren't the right kind of admin.
Hopefully the system admin will get back to you and give you a positive response on how to download the files, or fix the restrictions.
Have you been able to try to download on a PC from a different network connection, something not connected to the school's network. The download files are big, on the order of GB's each. But I think you can download the installation files in their entirety, then copy them to the other PC.
Brett_J's response about the run-time engine download was inaccurate, because you don't need just the run-time engine, but the entire development environment according to the screenshot in your original message. That makes sense because the NXT modules (I haven't worked with these myself) is an add-on to simplify a lot of the programming with in LabVIEW itself. The run-time engine is strictly the background routines that the OS needs in order for someone to run an application that was built into an .exe within the LabVIEW development environment on a different PC.
I think Brett_J's response about not using the NI downloader is helpful the downloader is used to get a quick start on downloading and installing the installation files. I think it assists in picking up where it left off in the event the download gets interrupted. But I think it truly only works if you are looking to install the software on the same PC you are downloading on.
