Lasso FileStream Problem

[pdbe]

I hope this is just a syntax error, but I am using Lasso's File_Stream tag to deliver PDF files and have a problem with the -Name part:

Text before a field works:

[File_Stream: -File=( Field: 'filestream' ), -Name=( 'randomtext ' + Field: 'Title' ), -Type='application/pdf']

and gives eg. "randomtext documentone" as the filename

But what I want is some text after the field:

[File_Stream: -File=( Field: 'filestream' ), -Name=( Field: 'Title' + '.pdf' ), -Type='application/pdf']

This returns an error rather than giving eg 'documentone.pdf' as the filename.

This is the error returned:

Error Message: No tag, type or constant was defined under the name null->replace with arguments: array: ("), (")

Error Code: -9948

Thanks for your help!