Hi, I have installed my domain, which until now has always worked on aruba.it keeping my hosting on siteground.

Except that you can't access the store again, even if you see the site.
Instead it appears in the administration panel
Warning: session_start () [function.session-start]: open (/ home /...../ public_html / shop / cache / sess_242td7nn2os4giqrksgse1o1r7, O_RDWR) failed: No such file or directory (2) in / home / customer / www / ......... public_html / shop / includes / functions / sessions.php on line 108

What can I do? Can anyone help me? Thank you