[NCC] Question about Yagi for Windows

[Ray Conrad NM2O]

I've installed Yagi for Windows and all other programs from the ARRL Antenna Handbook. I cannot open an antenna file in YW. I get an error message stating that the file is bad, and examine with word processor. It seems OK. I can copy the data into a new file, and it seems OK. 

Has anyone seen this?

Also, does the program optimize the antenna? That is a key feature of YO, which I've used several times. 

73,
Ray 
NM2O