windows 2008 scheduled task problem

I am running postgresql 8.4.3/ postgis 1.5 on a windows server 2008 R2

I am unable to get the shp2pgsql command to run as scheduled tasks.
There is no problem running any of the commands from the command line or
a python script.

Some sample commands are

shp2pgsql -s 900913 -I -d myshape.shp gis.myshape -u xxx -p yyy >
myshape.txt

or

%POSTGIS_PATH%\shp2pgsql -s 900913 -I -d myshape.shp gis.myshape -u xxx
-p yyy > myshape.txt

or

shp2pgsql -s 900913 -I -d myshape.shp gis.myshape -u xxx -p yyy | psql
-d mydb -U xxx -q

I do not get any output from the scheduled task.

The history tab in the task scheduler will show Task triggered/ task
started / task completed, and report the task successfully completed.

I am running the tasks under a system administrator account.

Any suggestions from someone who has a similar environment.

This is my first post to the list and I hope it is an appropriate place
for the question I and I have provided enough detail.

Ralph Dell