Why won't this script line work w/ QuarkXPress 6.5? It worked fine w/ 4.11.

-- script snip:
tell application "QuarkXPress"
 tell document 1
   set every text of every story where it is varSearch to varReplace
 end tell
end tell
-- 

The error is -10006

If I replace the variable names with actual strings, it works fine. Thinking
the problem had something to do with that, I tried the following:

set {varSearch, varReplace} to {"WWW-", "ASD-"}
set every text of every story where it is varSearch to varReplace

. . . and it worked fine.

I compared (using "log class of..") that command with mine and found
variables were all of class string. (Mine are set by display dialog, so I
use a second line to change Unicode text to string.)

Anyway, it's taking me to the edge!

Many thanks,

Dan