I'm still using GiP V2.94 (not updated yet) on Win10, and use a command line and enter PIDS into a batch file as below

    rem gettp.bat
    rem get_iplayer get tv show
    get_iplayer --get --pid %1

This gets the wanted TV programme every time.

But when I tried to download Part 3 of "New York: America's busiest city" (b07w10gz) I get the following error continuously scrolling

    (c) 2010 Andrej Stepanchuk, Howard Chu, The Flvstreamer Team; license: GPL
    ERROR: Last tag size must be greater/equal zero (prevTagSize=-1132302631) and smaller then filesize, corrupt file!
    INFO: Command exit code 1 (raw code = 256)
    WARNING: Retry recording for 'New York: America's Busiest City - 3. Episode 3 (b07w10gz)'
    INFO: File name prefix = New_York_Americas_Busiest_City_-_3._Episode_3_b07w10gz_default

Has anyone else experienced this? What was the fix?

TIA.

Problem resolved. I found a partial recording in my downloads folder. Deleted it and now all OK. Sorry for the disturbance.