Can not add to cart a product with more than one custom fi

[Lina2013]

Hello,
I have the following problem: if a product has just one custom field (size, for example), it does get added to cart, if a product has two customer fields - f.e. size and colour, I does not get added to cart. Strangely enough, on some PCs it's possible to add a product with two custom field to the cart in Internet Explorer, for Chrome and Mozilla it never works. Any ideas are much appreciated, I've been trying to resolve this issue for some time with no success whatsoever. Many Thanks in advance!