The 220 ohm resistors and 5k pots can be used with the more expensive LM117 and LM137 regulators. 120 ohms should be used with the LM317 and LM337, then the value of the pots should also be reduced.
The peak of the 24VAC is 34V and is reduced to 33V by the rectifiers. It will be higher with a low load current. The resistor and pots values shown will produce a maximum output of 30V, not 15V.
Make sure the pins on the ICs are correct. Also make sure you are using Name-Brand ICs, not cheap fake copies.