### Small formula window doesn't work in LO 3.5. Do I miss something?

I installed LO 3.5 from the libreoffice PPA. Everything works well up to now except the formula window. I try ADD - OBJECT - FORMULA on the LO Writer. The process begins but I can not see the small screen where we write a maths formula. So I try LO Maths but the same thing happened. As a result I can not write Maths Formulas. Do I miss something?

OS=Ubuntu 11.10