Maybe anybody knows what's going on here:

foxit.bat:
"C:\Programme\Foxit Software\Foxit Reader\Foxit Reader.exe" /t %1 %2
del %3
@echo "OK"

test.bat:
foxit.bat "datei1.pdf" "\\ibm1\EF0" "test.txt"
@echo "OK"

Called by command line test.bat prints the PDF on \\ibm1\EF0 and deletes test.txt.
Called by PHP exec("test.bat") it deletes test.txt but doesn't print the PDF.
No errors can be seen anywhere.
As you might guess, it's the printing I am after.
I would be grateful for some help.
Many thanks in advance.

Guenther