Notepad Replacer seems to have problems with filenames that contains multiple consecutive spaces. It appears to replace the multiple spaces with a single space. This causes the invoked replacement program to complain that it can't find the file.

e.g. the name "test file.txt" (2 spaces between test and file) gets converted to "test file.txt" (1 space between test and file).

Using version 1.1.2 under Windows 7 Enterprise 64bit

Yep, 1.1.3 works just fine.
Thanks for the quick fix.