PROBLEM Broken links after server change

[7Oops]

Hi all,
I seem to have a configuration  issue or version conflict somewhere in my new setup (I am just an amateur, approaching the modification and functional upgrade of an existing site.
Background: To be safe in learning efforts I installed XAMPP on my Win7 machine, downloaded the current GS version, then followed the instructions for moving an existing site to another server.
I also changed ports in XAMPP (:90 and :444) due to Skype conflicts.
Setup went fine, I can log in to my GS site as admin and do any modification per existing plugins (i18n etc...)
Now here is my issue: 
Some links don't work and I get errors like:
<a href="<br />
<b>Fatal error</b>: Uncaught Error: [] operator not supported for strings in C:\xampp\htdocs\getsimple\admin\inc\theme_functions.php:475

Stack trace:
#0 C:\xampp\htdocs\getsimple\admin\inc\theme_functions.php(544) : eval()'d code(13): menu_data('kontakt')
#1 C:\xampp\htdocs\getsimple\admin\inc\theme_functions.php(544): eval()
#2 C:\xampp\htdocs\getsimple\theme\Innovation\sidebar.inc.php(36): get_component('sidebar')
#3 C:\xampp\htdocs\getsimple\theme\Innovation\template.php(36): include('C:\\xampp\\htdocs...')
#4 C:\xampp\htdocs\getsimple\index.php(134): include('C:\\xampp\\htdocs...')
#5 {main}

thrown in <b>C:\xampp\htdocs\getsimple\admin\inc\theme_functions.php</b> on line <b>475</b><br />

Thanks for your support - and sorry if this turns out to be a stupid beginner's error.