HandleInvoke, Sanity failed. no string method in invoke packet

[Nick Payne]

This error seems to be happening when I use --tvmode=best and 
get_iplayer tries to download the program using flashhd1 - see terminal 
output below. I tried the download several times and this error happened 
each time, but at a different point in the file each time. When the 
error comes up, I can leave the terminal running for many minutes, but 
no further terminal output appears, and the bytes and percentage 
downloaded doesn't change. If I look at the folder ~/Videos/iplayer/ 
while this is happening, I can see that the size of the downloaded file 
is not incrementing at all, but if I run iotop in another terminal, I 
can see that rtmpdump is running and is still downloading 
something...but not to the specified output folder. If I press Ctrl+C to 
terminate the download and force flashhd2 download by changing 
--tvmode=best to --tvmode=flashhd2, then the download proceeds normally 
and completes successfully without any errors indicated.

Running on Linux Mint 17 amd64.

nick at nick-lm17 ~ $ get_iplayer --get 1051 --output ~/Videos/iplayer/ 
--tvmode=best
get_iplayer 2.86-2-g969bd34-ppa17, Copyright (C) 2008-2010 Phil Lewis
   This program comes with ABSOLUTELY NO WARRANTY; for details use 
--warranty.
   This is free software, and you are welcome to redistribute it under 
certain
   conditions; use --conditions for details.

Matches:
1051:    Storyville - 2013-2014: 30. Velorama, BBC Four, 
Cycling,Sport,TV, default,

INFO: 1 Matching Programmes
INFO: Checking existence of default version
INFO: 
flashhd1,flashhd2,flashvhigh1,flashvhigh2,flashhigh1,flashhigh2,flashstd1,flashstd2,flashlow1,flashlow2 
modes will be tried for version default
INFO: Trying flashhd1 mode to record tv: Storyville - 2013-2014: 30. 
Velorama
INFO: File name prefix = 
Storyville_-_2013-2014_30._Velorama_b048wqcc_default
RTMPDump v2.4-n87-gita9f353c-ppa8~saucy
(c) 2010 Andrej Stepanchuk, Howard Chu, The Flvstreamer Team; license: GPL
Connecting ...
INFO: Connected...
Starting download at: 0.000 kB
INFO: Metadata:
INFO:   duration              3518.24
INFO:   moovPosition          36.00
INFO:   width                 1280.00
INFO:   height                720.00
INFO:   videocodecid          avc1
INFO:   audiocodecid          mp4a
INFO:   avcprofile            100.00
INFO:   avclevel              41.00
INFO:   aacaot                2.00
INFO:   videoframerate        25.00
INFO:   audiosamplerate       48000.00
INFO:   audiochannels         2.00
INFO: trackinfo:
INFO:   length                87956000.00
INFO:   timescale             25000.00
INFO:   language              und
INFO: sampledescription:
INFO:   sampletype            avc1
INFO:   length                168875008.00
INFO:   timescale             48000.00
INFO:   language              und
INFO: sampledescription:
INFO:   sampletype            mp4a
460.312 kB / 5.44 sec (0.1%)
WARNING: HandleInvoke, Sanity failed. no string method in invoke packet