Airtime on low-power computer (NSLU2 etc.)

The NSLU2 is a low-power NAS originally, but it runs Debian and so I thought I'd try to install Airtime on it.
I've later found that 1GHz is recommended for Airtime and the NSLU2 only has 266MHz.

Installation went without problems (1.9.5) but when trying to access the administation page for Airtime, it takes ages to load the login screen and after that I get a PHP error:

Fatal error: Uncaught exception 'Zend_Session_Exception' with message
'Zend_Session::start() -
/usr/share/airtime/library/Zend/Session.php(Line:480): Error #2
session_start(): Function spl_autoload_call() hasn't defined the class
it was called for Array' in
/usr/share/airtime/library/Zend/Session.php:493
Stack trace:
#0 /usr/share/airtime/library/Zend/Session/Namespace.php(143):
Zend_Session::start(true)
#1 /usr/share/airtime/application/models/Preference.php(68):
Zend_Session_Namespace->__construct('title_name')
#2 /usr/share/airtime/application/Bootstrap.php(90):
Application_Model_Preference::GetHeadTitle()
#3
/usr/share/airtime/library/Zend/Application/Bootstrap/BootstrapAbstract.php(665):
Bootstrap->_initTitle()
#4
/usr/share/airtime/library/Zend/Application/Bootstrap/BootstrapAbstract.php(618):

Zend_Application_Bootstrap_BootstrapAbstract->_executeResource('title')
#5

/usr/share/airtime/library/Zend/Application/Bootstrap/BootstrapAbstract.php(582):
Zend_Application_Bootstrap_BootstrapAbstract->_bootstrap(NULL)
#6 /us in /usr/share/airtime/library/Zend/Session.php on line 493

I know there's no native ARM support for Airtime and the hardware on the NSLU2 is not very strong, but is it entirely unfeasable to run a test radio station on it with Airtime?

Thanks in advance!