Read values from Trigger out

I have created a trigger function.

could somebody tell me how I get the values from the insert in the trigger
function.
I tried the function

SPI_getvalue(trigger,tupdesc,attnum)

but after starting the trigger, I become this terminating output:

pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.
We have lost the connection to the backend, so further processing is impossible. Terminating.

thank's for your help
--
Thomas Egge