Error trying to execute Drainage Line Processing

[AnaCristinaRodrigues]

Hi guys!

It's the first time I'm working with GIS.

I'm using Hec-GeoHMS, but I can't get my Drainage Line Processing done.

The error in red says:

Attempted to acess a missing method.

Failed to exacute (DrainageLinerocessing).

Here's a printscreen:

Can you help me with the motive/solution?

Thank you very much.

Ana