I have an ubuntu server and a windows XP client running Cygwin. The server ssh's into the client and tries to execute a shell script with some params, with the following command:

ssh user@IP_ADDR 'sh /home/user/project/clientside 2 5 7 6 9 5 7 IP_ADDR'

where IP_ADDR is the IP address of client.
However, while doing so, I get the following error:

Access is denied.

Thinking this might be a user permissions error, I tried running sh /home/user/project/clientside 2 5 7 6 9 5 7 IP_ADDR on the client, on Cygwin, while logged in as user.
This works as expected.

Then I thought that this might be an error with the login that I use when I ssh into the client. So I executed this instead:

ssh user@IP_ADDR 'whoami'

and got back user.

This happened even after I did chmod -R 777 /home/user/project on the client, in Cygwin.

For kicks, I got on Cygwin on the client and did ssh localhost and manually executed sh /home/user/project/clientside 2 5 7 6 9 5 7 IP_ADDR.
This worked as expected.

However, when I did ssh IP_ADDR from Cygwin and did ssh localhost and manually executed sh /home/user/project/clientside 2 5 7 6 9 5 7 IP_ADDR, I get the same Access is denied. error.

Why is this happening? How can I fix this?

By the way, both the server and the client have each other's rsa public key for passwordless ssh