The file you need for openpli 4.0 and connected to this thread is mips32el.ipk. You are trying to install mipsel version which is incompatible.
Use either of these commands;
opkg install -force-overwrite /tmp/*.ipk
ipkg install -force-overwrite /tmp/*.ipk
Or in DCC click tools > packages > upload package.
I've also tried to install mipsel32 but i get the same result..
I also forgot to mention that I used this tutorial
http://linuxsat-support.com/showthread.php?t=13502
Which means that I am using Ubuntu via Virtualbox, I have FTP'ed the file to /tmp/ folder, but I always get the same result which is ""Done - installed, upgraded or removed 0 packages with 0 errors""
But the main problem is the one with opkg
EDIT: don't see me as a cheap guy, I am going to buy a DM800 or better however this is just for testing purpose, I want to first learn how it works and after I have learned the main purpose to install TSpanel I am going to buy the box :)