No, not because it isn't safe, but because they are likely to be too big.
The file contains the contents of memory, etc. at the time of the crash, but I doubt they would have sensitive data.
You can use the ftp server to upload big files. Upload them to
ftp://ftp.avast.com/incoming - 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. Once you have done that post on the forums that you have uploaded them.
Before you do this make sure that the files have unique names so they can be identified as yours, e.g. ellishk97-filename (where filename is the existing file name, so you are just putting four forum name in front of it).