For a school researchpaper I need to work in SPSS and have to recode some items, whenever I enter the dialoguescreen where I have to fill in the name of the old value, I can't type anything in, I hear an error sound but no error message. I don't know how to fix is.

If you mean to fill in the old value on the Old and New Values subdialog, you enter the value in the first field. If it is a numeric variable but you try to enter an alphabetic character, the dialog will beep and reject the character. You will in values, not names.