acroread expr syntax error

Here the solution:

https://fcp.surfsite.org/modules/newbb/viewtopic.php?topic_id=26864&forum=12&post_id=114769

Summary:
I edited the startup script and and added two lines of code ater commenting out the old one as follows :-

418# echo $mfile| sed 's/libgtk-x11-\([0-9]*\).0.so.0.\([0-9]\)00.\([0-9]*\)\|\(.*\)/\1\2\3/g'
419 echo $mfile| sed 's/libgtk-x11-\([0-9]*\).0.so.0.\([0-9]*\)00.\([0-9]*\)\|\(.*\)/\1\2\3/g'

644# MIN_GTK_VERSION="240"
645 MIN_GTK_VERSION="2040"