well this is a MS Windows limitation.
As suggested by Lindsay you can workaround this by a network share reducing the path.
using a command line example:
net use z: \\my destination\folder\path
then use z: as your destination to copy over
xcopy <your sourcerepositoryfolderpath> /E/K/Y
Be careful with /Y as this will overwrite any existing files with same names in destination (may you don't want just take this parameters out).
/J