Exactly. If you are new to the Dreambox an FTP program is the easiest way of adding keys or files to the Dreambox unless you use direct download through internet,. Especially plugins, cams and keys like to be on 755 chmod. Very easy to do as Rolf said, right click on the file (or all files in a directory and chmod to 755.
the first numbers sets permissions for the user himself (ie you) the second is for the group you belong to (nothing to do with cardshare or anything,its unix/linux lingo!) the third is for everyone else (all net users)
7 means the the user can read,write to,and execute the file 7 is really standing for its binary equivalent ...
which in turn means 'rwx' ... for "read,write,execute"
so, 5 would be 110 in binary, which would be 'rw-' ... so reading and writing is allowed, while executing is not allowed.
so, if you gave a binary file the permissions 555,it would mean that the user (the first 5) can only read and write to the file,but is not allowed to execute it.so a softcam in /var/bin will not work with 555. if you make it 755 it will then have execute permissions so will work.in fact it will also wotk with 750 or perhaps even 700 ...
for more info do a google for "chmod unix man page"
in general all files you place in /var/bin will need to have execute permission.files in /var/keys do not need execute,they just need read.though there is no harm in giving them execute anyway