Running the DB2 IMPORT statement below :
“import from MYTable.ixf of ixf messages msg.txt INSERT INTO MYSCHEMA.MYTABLE”
the error response in the DB2DIAG.LOG was :

Error from Import/Export or Load Processing
“Log File has reached its saturation point”
DIA8309C Log file was full.

One solution to this problem , is to use COMMITCOUNT , this allows a COMMIT after every n records are imported.
By amending the initial sql statement to :
“import from MYTable.ixf of ixf commitcount 100 messages msg.txt INSERT INTO MYSCHEMA.MYTABLE”
this allowed the the commitment after every 100 rows