I am trying to initialize a global variable that will be used as part of the file name (used in tFileOutputDelimited) that is later created within a log catcher subjob.  That is, this all occurs within a LogCatcher subjob and this subjob can be 'called' many times -- hence the need for uniquely named log file / log catcher output.

Subjob Flow:
                    tSetGlobalVar  (global var set here)
                      ^                 
                      |
tLogCatcher->tMap->tFileOutputDelimited (use of global var as part of file name to make file name distinct. File contains default schema/contents sent by tLogCatcher)

Question:

It works for all files except the first file.  So I get files -- ordered by creation date first to last -- like (NOTE: global var is the random 6 digits of the file name):

null
file1_123455.log
file1_234335.log
file1_343223.log

Why does this not work for the first file?  That is, the null file is there because the global variable is not populated yet subsequent times it works fine.  The null file does contain the tLogCatcher data, as does all the other subsequent files.
I guess I need to know, within a tLogCatcher subjob, how can I assure that the global variable is set before I send the tLogCatcher default information to the file whose name includes the global variable?