[NOTE: I work with ASE, I do not work with the SAP application, so strictly from a ASE point of view .... ]
1 - The JS details mention trying to connect to port 4903; does netstat show any (listener) activity on 4903? What are your sql.ini entries for this ASE instance and the associated JS agent? Are there any messages of interest in the JS errorlog (by default should be in same directory with the ASE errorlog)?
2 - There's a solved case @ sybase.com (case # 11576917) that has some similarities with your JS details; the case mentions that the client had disabled IPV6 on the server, but after enabling IPV6 the JS issues went away; does the host have IPV6 enabled?