mb_substr cant be used on PHP 5.2.6

Fatal error:

开发者_StackOverflow

Call to undefined function mb_substr()

After moving to my dedicated server (hypervm CP), I got lots of errors.

How do I solve this problem?

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It looks like the mbstring extension, which provides that kind of functions, is not installed or enabled : if it was enabled, you'd have a block "mbstring", in the output of phpinfo().

If you are admin of your server, a first idea might be to check for something like

extension=mbstring

In you php.ini file.