You can remove the character with the Filter function or replace it with a "filename permitted" character using the substitute function.
Example: Substitute ( Get ( CurrentDate ) ; "/" ; "_" )
will replace the / character--not allowed in a file name, with the underscore. And you can subsitute out multiple characters by setting up square bracketed pairs of substitution text.
You might look up Substitute, Filter and Trim in FileMaker help to learn more.
But the period is permitted as the character in a file name so other issues might be preventing your PDF from being saved to the specified location.
Here's a thread on a Save As PDF script that you can use to compare its example script to your own: Found Sets to PDF with unique file names
Thank You. Perfect.