The number of spaces in the sample you posted didn't match what you are trying with the cut command. There may or may not be multiple spaces to pad the number to some specific length so it would probably be better to simply pick out the first non-space token from that.
If you have control over how those files are generated in the first place, it would perhaps be better if they simply didn't contain the file name. Or do you need it for other reasons?
wc -l <./pmroot/TgtFiles/ppax5.dat>.stat1a.tmp
Note the input redirection; wc simply prints the number, no file name, when invoked on standard input.
As a side remark on coding style, the cat isn't really necessary in your original code; cut accepts a file name argument, too: