i assume the pump is being mounted externally (for a leaky pump wouldnt matter with an internally mounted pump). Did you put teflon tape on any fittings that screw into the pump?
are you correctly using BARB fittings and stainless steel or plastic clamps or zip ties to hold everything tight? Are they the right size? You have have to really put effort into getting the barbed fittings onto the vinyl if you have sized everything right. I didnt even need to clamp my stuff but I did just in case.
i dont know how the vinyl connects to the pump but did the pump come with any special fittings for vinyl tube? My ehiem pump came with a wierd screw to lock fitting that took some figuring out but once i got it tightened up it was leak proof.
pictures would help us troubleshoot as well
