1) Actually it's an error message:
'Error 33353: end of paragraph cannot be found'
How should I proceed from there?
Try to "Fix Document", that is in Trados submenu in Word. Or simply insert a paragraph mark as Ralf advised you.
2) Speaking of text boxes, in some cases, when the font used is Arial, I type in the translation in Greek and everything is OK until I try to close the segment and proceed to the next one. The translated Greek text reverts to other font characters which are incomprehensible to me!
Change the font of the whole document (before you begin translating it in Trados) to the one that has no problems with Greek. (For example, I change Arial to Times New Roman for Russian), complete your translation and after you clean the text, change the font to original one, i.e. Arial.
It's not difficult: Edit > Select All and choose the font you want to use.
[Edited at 2004-07-30 15:35]