mxCreateString not work for vc6.0 and matlab

Hello,I meet a problem with transfer string type parameter from vc6.0 to matlab7.0.

situation: I used mcc -B cglsharedlib ... to create .lib *.dll *.h and *.ctf files.the type of parameter in the interface function is string.for example fun(mxArray fileName),fileName is type of string.

problem:

It works well in my computer.But when I use released application in a computer which MCR is installed,it not work. so I tried to test a function without type of string parameter,It works well. | once type of string parameter included,it failed to work| .

Please help me.