Limited parameter length for source cmd in Tcl shell

when the interactive shell is running with Tcl language, the source command fails if filename length is higher than 50 caracters.
Why ?!

Ex: source d:/testforkomodoIDE12/testforkomodo12/testforkomodo12/test.tcl => couldn’t read file “d:/testforkomodoIDE12/testforkomodo12/testforkomod” no such file or directory
source d:/testforkomodoIDE12/testforkomodo12/test.tcl => OK !

I’m not sure what that command is @CRo. Could you elaborate? Is that a Tcl command?