SAP Note 18864 - SAPcomm: no connection to SAP System

Symptom:

The attempt to establish a connection to the SAP System fails.
Error message in the SAPcomm log (component scmisap):
E1503 Cannot ALLOCATE QND (!)
E1508 SAP CPI-C error code (451) open of side info file failed

Cause and prerequisites

SAPcomm finds its "own" sideinfo file, but the entry requried for establishing the connection to the SAP System is incomplete.

Solution
Add the line "TP=" to the entry in question; "Dispatcher Service" generally has the format:
sapdp (sapdp00,...) (installation-specific).