epimitheas, thank you for the start! However, I don't see anything translated in VirtualBox_el.ts, it even lacks your name. I've added your name and the language name myself but keep in mind that the translation won't be added to the distribution until the amount of translated items reaches the 50% limit (note that you must take both .ts files from SVN and continue your work on them, not on your local copies!). Also, you didn't provide us your email which is a requirement too.
jose1711. I will repeat. The files you attached are kind of wrong: they are from the unsupported Qt3 version of the VirtualBox frontend (i.e. from the src/VBox/Frontends/VirtualBox/nls
directory). You need to take them from the src/VBox/Frontends/'''VirtualBox4'''/nls
directory (simply download using these links: http://www.virtualbox.org/svn/vbox/trunk/src/VBox/Frontends/VirtualBox4/nls/VirtualBox_sk.ts and http://www.virtualbox.org/svn/vbox/trunk/src/VBox/Frontends/VirtualBox4/nls/qt_sk.ts if you are unable to work with SVN)! I've merged them to the Qt3 directory though since they belong there. But keep in mind that these updates will not appear in the VirtualBox4
directory, you will have to put them to Qt4 .ts files manually.
Pau, I've merged your update however could you please comment on what are the other two archives attached by rbuj after you?
rbuj, thank you but first please tell what did you attach and why and who you are :) The Catalan translation is maintained by Pau Iranzo now so you should coordinate your efforts with him. I left your files untouched so far.
Updates to the Greek, Slovak (Qt3), Catalan (but not ca_2 and ca_ES), Romanian, Czech and Chinese are merged to SVN.