Smarty errors

[ping]

I get lots of smarty errors, usually at random when I try to logon.
They also appear when I try to submit a site via the submit.php

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[David]

Have you recently upgraded?
Is this 3.0.2?

[ping]

Yep this is the latest version and all the smarty errors that I seem to get quite randomly are all about this SmartyValidate.

[ping]

Any ideas ?

I also get a random error in admin panel when editing or adding links :
Fatal error: Cannot use string offset as an array in admin/init.php on line 228

To fix it I need to empty my /sessions/ directory on the ftp.