Hi,
Looks like the partner profiles are not defined correctly or system may be down at the time of import.
Have you checked in R/3 source system whether you have an entry mainatined in table "RSBASIDOC" with your BW system?
Have you performed RSA1--> Source systems--> Right Click on R3 Source System and click RESTORE CONNECTION, provide the ALEREMOTE Source System userid and password. It sets automatically partner profiles.
Do a system restore if you have authorisation else ask your basis people to check partner profile definitions etc. in tcodes WE20, WE21 whether they are defined correctly or not.
If everything is correct then might the source system is down at the time of import.
Try to re-import transport request once again.
Srikanth.