you have to make the left and right edges line up… in ai, select all you layers, and duplicate them (copy and paste). group the new layers and position the so they are lined up vertically. then drag the duplicate so the left edge lines up with the right edge of the original.
do the lines line up? if they do, it should wrap around a cylinder.
if they don’t you need to make sure they do. try using guides to line up the bottom edges of the lines on one side of the texture to the top edges of the same colored lines on the opposite side. then test it again using a new duplicate.
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW