OK, well either way - have you tried it with the script name encased in quotes as shown above? Has ScriptB been run on it's own to ensure it isn't throwing some unexpected error back not being captured?
I haven't noticed many errors in the online TSL help file they provide since 7.5. I'm up to 8 know and it is a good refresher when I haven't used a command in a while.
My comment on the documentation was not based on errors but based on lack of completeness. If I knew what I was doing I wouldn't need the documentation. Since that is true the documentation could at least be complete.
Select Settings>General Options>Folders.
Take a look at the "Search paths for called tests"-list.
Does it contain an entry "."?
If no, add it - this entry is required to call tests that are in the same directory (without using the full path inside the call-statement).
PS: If the test was NOT called, WinRunner should write an error "Test not found in the search path" into the result report. But you wrote, that there are no errors. Maybe you could write a report_msg or something like at the beginning of your scriptB to see if it was called or not...