Question

i downloaded and ran instant rails and i got that message

how do i fix this problem?

what is the other application that might be using this port?

Answer 1

To find out which process is using a port on Windows run netstat -ano at the command line. It will print a list like the following:

Proto  Local Address          Foreign Address        State           PID
TCP    0.0.0.0:135            0.0.0.0:0              LISTENING       1784
TCP    0.0.0.0:445            0.0.0.0:0              LISTENING       4
TCP    0.0.0.0:80             0.0.0.0:0              LISTENING       2460

Look for a line with a local address using the port you are interested in (it looks like Instant Rails tries to start Apache on port 80) and then check the PID in Task Manager. In the above example, port 80 is being used by the process with process id 2460.