mkdir() error when installing pear's xml_fastcreate

[newbieewwa]

Hi:
I installed a local pear copy on my share host. It looks fine. Then, I try to install pear's xml_createfast package, it shows a lot of errors like:

mkdir(): open_basedir restriction in effect. File(/usr) is not within the allowed path(s):

I wonder if the configuration's installation dir is wrong or permission problem?Do you have any idea how to make it work ?

Thanks in advance!