PLease - i need help can not get in ADMIN MODE

Hello,

i'm new here, i have installed the mobile joomla com. After that the english language was only withe the Database names to see.
Runs very good, but since this nite i come not in the joomla mobile admin menu. After a second loading in browser on admin page i get a white site. I can nothing change. But the modules and plugins works god.
my homepage www.haus-gerlinde.com

PLease help me 

Mike
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mac OSX 10.8, joomla 1.5, joomla 2.5.7, virtuemart 2.0.12

Do you have error messages in error_log file?

How can i see the logfile? And what have i look for?