filename=[csv file]
outputfolder=[Output folder, ignore this setting to use the same folder as the source file]
rowcount=[Number of rows per file]
firstrowheader = 0 or 1 (default 0)
repeatheader = 0 or 1 (default 0)


eg. 
CSVSplitter filename="c:\data\big.csv" outputfolder="c:\data\output" rowcount=10000 firstrowheader=1 repeatheader=0

Test the program exit code to check the result

> echo Exit Code is %errorlevel%

Level  0 OK
Level -1 ERROR