Hello, I am having problems too, did you solved yours?

I think we did. The most important issue was the heat inactivation of some enzymes - it seemed like they didn't deactivate and a clean-up kit had to be used to get any results. The DNA amount for the reaction had to be closer to the upper limit (1ug) and the clear buffer was the only one working. After the ligation we used the highly competent dh10B cells (chemocompetent). For electrocompetent cells cleaning the DNA after the ligation was necessary but the majority of it was lost and the transformation efficiency was low.