You need to send each line of data to the server with a $crlf at the end. You are automatically doing this by sockwrite -n
-n adds a newline if there isn't one already. The HTTP header you are sending must be ended by a $crlf.

Code:
sockwrite -n $sockname GET /aw-cgi/eBayISAPI.dll?TimeShow HTTP/1.1
sockwrite -n $sockname Host: cgi3.ebay.de
sockwrite $sockname $crlf


that should work then