Nero 5.0.4.8 - close cd doesn't work

[LeTrua]

i have a HP 7200i and am not able to close my cds (german: "fixieren der cd ist fehlgeschlagen"). I just tried to create a normal backup but it says I'd have to close ("fixier") the cd to have enough space on it (either if I choose 630 or 650 mb to put on the cd). after burning the cd can't be read in my TEAC (TOC is missing), but in my hp!
please help, other programs like winoncd don't have this mistake.