I have neither satellite nor cable but I think I might know what your problem is.
Your DVD recorder probably has a built-in (probably analogue) tuner which is where it expects to get a signal from, unless it's 'told' otherwise.
When you connect some pairs of devices together (such as TVs, VCRs, DVD recorders, Freeview boxes, Sky boxes, Virgin boxes, etc), they communicate with each other, so that the 'receiving' device recognises that it's expected to handle a signal from the other device (rather from its 'default' source). With other pairings it's necessary for the user to tell the receiving device which signal source it should use.
Your old Virgin box sent a signal to the DVD recorder which said "record from me, not from your own tuner". Your new box isn't sending that signal (or the signal is not being recognised), so the DVD recorder is trying to record from its own tuner. (So, if you've not got a TV aerial plugged into it, it will report "no signal").
The solution is to check that your DVD recorder is set to record from 'AV' (rather from any numbered channel). Look for a button on the handset labelled 'AV', 'AV1', 'AV2', 'Line In', 'L', 'L1', 'L2', 'Ext' or 'Aux' (manufacturers can't seem to agree on what to call it!) and ensure that you use that button to choose the 'channel' when recording.
Chris