well i had a little probles with x-terminal but t solve this....
for the people who still have problems i change ONLY one symbol
example:

first Type
root
(press enter, Then

cat psn350payload.bin > /proc/psfreedom/payload
OR
cat hermes_payload.bin > /proc/psfreedom/payload

I ONLY ADD : / (before psn350payload.bin or hermes_payload.bin)
like this:

cat /psn350payload.bin > /proc/psfreedom/payload
OR
cat /hermes_payload.bin > /proc/psfreedom/payload

And this simple thing solve my problem... i hope that help somebody!