Bounds are weird. Despite their looks, they’re not lists. To get at individual items, you’ll have to coerce it to a list.
Operating in points for these kinds of operations will save you some grief, since the conversions Quark does can be unpredictable.
Try something like the following:
set bnds to {"720 pt", "-7.2 pt", "792 pt", "7.2 pt"} as list
repeat with myItem from 1 to count of bnds
set item myItem of bnds to item myItem of bnds
end repeat
tell application "QuarkXPress™ 4.11"
tell document 1
tell page 1
repeat with x from 1 to (count of text boxes)
set {theY, theX, the2ndY, the2ndX} to (bounds of text box x) as list
-- coerce to real
if ((theY) as real) = (720) then
display dialog "The first Y matches."
end if
-- coerce to text
if (theX as text) = (item 2 of bnds) then
display dialog "The first X matches."
end if
end repeat
end tell
end tell
end tell
Luck,
–tet