Bug fatal error setting up

after installing this and trying to run the setup i get this error in my admin :-

Fatal error: Class 'vb_optimise' not found in/home/craftyca/public_html/includes/adminfunctions_options.php(634) : eval()'d code on line 56

i have installed it on my test site 4.1.10 and it worked perfect.

the file error i have checked and there are no differences in the file.

what would be the problem

many thanks

Please ensure you've uploaded all files to their correct directories.

i have installed them in correct directorys,
i checked 10 times,
1 to admincp
1 to includes/xml
and the other is main root folder vboptimize folder.

followed exact same rout as i did on the test site.

---------- Post added at 23:28 ---------- Previous post was at 23:17 ----------

i have gone to check on firefox and its showing as setup, so google chrome must have a refrews issue