If sys() is called with wrong parameter values then it returns the wrong (or at least useless and misleading) message that sys(#,#,#,#) is undefined.
A helpful message would be: "Specified number of rows not equal to number of elements"
Even better: just ignore the tast two arguments, as the last can't be different from 1 and the second last must equal the number of elements given.
Left example: numeric evaluation, right example symbolic evaluation
BTW, I don't understand why the message appears only with numeric evaluation. In symbolic evaluation, there is no reason to not complain.
SMath Studio: SMath Studio Desktop 0.98.6103.14491, x64
OS: Microsoft Windows NT 6.1.7601 Service Pack 1 (Microsoft Windows 7 Professional , x64)
Screen: 1920x1080 px, 96x96 dpi
Localization: separator=<semicolon>; decimal symbol=<comma>; system decimal symbol=<comma>; language=GER
Frameworks: CLR 2.0.50727.5485
installed versions:
v2.0.50727 2.0.50727.5420 SP2
v3.0 3.0.30729.5420 SP2
v3.5 3.5.30729.5420 SP1
v4
Client 4.6.01055
Full 4.6.01055
v4.0
Client 4.0.0.0