watch window error:cannot load from a non -primitive location

hello sir i am working on a ccs 3.3v ,while i am debugging the project some part of my code contains file functions fopen and fscanf trying to read a float value from a.txt file and assigning it to the variable unsigned type ,when i am trying to watch fopen functon in watch window iam getting an error :cannot load from non-primitive location and float value from txt file is not getting read by fscanf function also .please suggest me a slution for this  .