The dump file may help the developers, the file is likely to be large, zip it to compress. Upload it to
ftp://ftp.avast.com/incoming - Using Internet Explorer, Connect to the link and drag the file into the Right pane and drop it, that starts the upload, you don't have read access to this folder. Give the zip file you are uploading a unique name, so they can identify it.
It might not be a bad idea to create a text file (readme.txt) with any relevant information, avast topic URL, user name, etc. etc. in the zip file.