Failed to connect to an IPC Port - c# Script

Hello,

Previously the c# component I had written was working fine. It takes a List of Point3d and does operations. However now when I connect the ptTree variable to a list of points, the component throws the following error:

1. Failed to connect to an IPC Port: The system cannot find the file specified.
(line: 0)

Any idea what might be causing it? If I disconnect the variable, everything is fine again.

Cheers,

Antony