tipitaka.net accessibility problem

Dear Members,

I received a message from Ria Glas of The Netherlands about being unable to
access the translation keys to the lessons of several Pali primers (Series A
to F) on the following page:

http://www.tipitaka.net/pali/palidd/

Ria has tried to reach Yong Peng but hasn't heard back and has been trying
to access the keys for the past two months.

Is anyone here aware of the problem and can give an explanation?

Best wishes,

Jim