Resolution:
This message means that the data in a field of a message that we are trying to write to file was not correct.  In this example the message type was "info" which is defined as having a single field of type string.  The grammar defined for a message type is not used to type check the message when it is being built or sent, it is only used to determine the correct format when the message is being printed to the screen or logged to a file (used as the formatter for an fprint* statement).
In the following example the correct field type (string) is used and therefore would not cause a Warning in the trace file:
msg = TipcMsgCreate(TipcMtLookupByNum(T_MT_INFO));
TipcMsgAppendStr(msg, "foo ");

But, if the first field is not of type STRING, such as:
msg = TipcMsgCreate(TipcMtLookupByNum(T_MT_INFO));
TipcMsgAppendInt4(msg, 42000000);

AND the message logging feature is being used then the Warning TAL-SS-00102-W will appear in the RTserver or RTclient trace file. This Warning message will be logged but none of the messages fields will be displayed. This Warning is benign and will not affect the receipt of the entire message by any subscribing clients.