REED SOLOMON Coding with PSK modulation in Rayleigh fading channel-SIMULINK

hello,
I am modeling REED SOLOMON Coding(n,k)=(7,3) with 8-PSK modulation in Rayleigh fading channel,using SIMULINK.When I use multi path Rayleigh fading channel block, I get this error:
[The minimum input width must an integer scalar > 0]

Can any one plz help me to figure out this problem! Start a New Thread