Hi,
without having at least basic info about the sequence of operations/commands you tried, one can only guess...
There surely is a mismatch in the declaration of the variables.
If you want to read the value from a file, the usual way is to store it in a TABLE or an ARRAY. You can not store that file's data in a scalar, even if it contains one single value. You do can declare (*DIMension) an array to have unit length, so it will expect only one value.
Any time you will have to access to this value, however, you will have to write something like blah=array(1).
Hope this throws some light somewhere...
Regards