I just bought some Venture skateboard trucks (Black and white, Lows). And Doh doh bushings.Major problem?

I have used Doh dohs in the past (the hard yellow ones) and loved them. Though this time i put them in and they were fine, but after skating them in and tightening them (i like trucks as tight/hard as can be) I did an ollie and the front truck tilted completely sideways as if i was carving with loose trucks and didnt come back until i jumped around on the other side. By the way i have had alot of trouble with trucks as i can never get them to stay tight. Thanks alot to rany answers, and if they are no good or it isnt the trucks its the bushings i can get my money back tomorrow. (85.95) Thanks again.