I suppose you should reinstall psa-locale-base-en-*.rpm from
rpm_*_7.5/base/ directory to correct the labels.
If it doesn't help there is may be problem caused by the fact that Plesk
7.5 Reloaded supports German and Spanish LP at the time only.
http://www.sw-soft.com/en/download/lp/.
If you have some different LP as default in the control panel before
upgrading it may cause the issue. To fix the problem you should setup
default LP to en back:
* #mysql -uadmin -p`cat /etc/psa/.psa.shadow` -e'update psa.misc set
val="en-US " where param="def_locale"';
* reinstall psa-locale-base-en-*.rpm
Now there should be english language pack in the control panel.