Unfortunately, the provided information does not help us much in reproducing the error. I'm afraid we could not be of much help unless we reproduce the issue on our side. It will be best if you can open a support ticket and send us a simple running project (incl. your custom skin, CSS, images, DB backup if needed and so on) demonstrating the problem (and step-by-step instructions on doing so). In that way we can reproduce and pinpoint the problems you're facing on our side, understand the logic of your application and provide a solution.
All the best,
the Telerik team