Default Unable to install SDE 70b IT

I'm not quite sure but I have never been able to get this tablet rooted. To be clear, this is the HC version (IT2 I guess), running 2.4.81

For starters I would just like to do it the easy way and get SDE on there, the way it's described here and on the Archos site. But every time I've copied the file over it just gives me "update failed (1)". I've now tried every conceivable combination of cable pulling, unmounting, waiting, different files,... the outcome is exactly the same.

I didn't see this problem mentioned anywhere so I was wondering if anyone experienced this or could point me to the most painfree way of finally rooting this tablet?

Thx in advance.
[Bootloader] 0.33.0012
[Recovery] RA-passion-v2.2.1
[ROM] [GRK39F] N1 2.3.6 OTA ROM v2 (deodex, root, zipalign., busybox, A2SD, TBAlert)
[Kernel] Stock