apt-get -- Size mismatch errors

Hello,

I've done many changes to my ReadyNAS Ultra 4, and currently I want to install the motioneye frontend (https://bitbucket.org/ccrisan/motioneye) for an already running motion (http://www.lavrsen.dk/foswiki/bin/view/Motion).

Besides other stuff, this also needs ffmpeg which I am trying to install using apt-get. Unfortunately this fails:

ReadyNAS:~# apt-get install ffmpeg
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  libavcodec52 libavdevice52 libavformat52 libavutil50
The following NEW packages will be installed:
  ffmpeg libavcodec52 libavdevice52 libavformat52 libavutil50
0 upgraded, 5 newly installed, 0 to remove and 2 not upgraded.
Need to get 1192kB of archives.
After this operation, 3658kB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://www.readynas.com 4.2.26/ libavutil50 4:0.6.7-0.netgear1 [80.5kB]
Get:2 http://www.readynas.com 4.2.26/ libavcodec52 4:0.6.7-0.netgear1 [679kB]
Get:3 http://www.readynas.com 4.2.26/ libavdevice52 4:0.6.7-0.netgear1 [43.1kB]
Get:4 http://www.readynas.com 4.2.26/ libavformat52 4:0.6.7-0.netgear1 [253kB]
Get:5 http://www.readynas.com 4.2.26/ ffmpeg 4:0.6.7-0.netgear1 [136kB]
Fetched 1124kB in 4s (242kB/s)
Failed to fetch http://www.readynas.com/packages/4.2.26/f/ffmpeg/libavutil50_0.6.7-0.netgear1_i386.deb  Size mismatch
Failed to fetch http://www.readynas.com/packages/4.2.26/f/ffmpeg/libavcodec52_0.6.7-0.netgear1_i386.deb  Size mismatch
Failed to fetch http://www.readynas.com/packages/4.2.26/f/ffmpeg/libavdevice52_0.6.7-0.netgear1_i386.deb  Size mismatch
Failed to fetch http://www.readynas.com/packages/4.2.26/f/ffmpeg/libavformat52_0.6.7-0.netgear1_i386.deb  Size mismatch
Failed to fetch http://www.readynas.com/packages/4.2.26/f/ffmpeg/ffmpeg_0.6.7-0.netgear1_i386.deb  Size mismatch
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
ReadyNAS:~#

Same result with apt-get update or with --fix-missing.

To me it seems the ReadyNAS server has an inconsistency between the archive list and the packages do be downloaded, is there any way to correct this on my systems or bypass this ?

Thx,
Max