Only variables should be passed by reference

I'm having the same problem. I'll try to be as detailed as possible here to help track down the issue.

System Settings
Windows Server
Apache 2.4
Drupal 7.22
Field (Field) Paths - 7.x-1.0-beta3
Multiupload Imagefield Widget - 7.x-1.2
Multiupload Filefield Widget - 7.x-1.11
Multi-site Install

Error
Strict warning: Only variables should be passed by reference in filefield_paths_filefield_paths_process_file() (line 66 of D:\htdocs\d7sb\sites\all\modules\contrib\filefield_paths\modules\filefield_paths.inc).

First Test - Image Field - ERROR
Trying to upload images for a content type called Image Gallery. Field is set to use the Multiupload Widget. Receive the error once for each file uploaded. Uploading one image at a time or multiple images and saving netted the same results.

File Path = images/galleries/[node:title]
File Path Options = Cleanup using Pathauto checked
File Name = [file:ffp-name-only-original].[file:ffp-extension-original]
File Name Options = none checked
Number of values = unlimited
Upload destination = public files
Image File names tested: dogvsstrideroutlands.jpg, download.jpg, einstein-1920x1080.jpg

Second Test - Image Field - ERROR
Changed the widget to standard Image. Uploaded a new image. Same error. In both of these examples the images end up in the correct location "sites/test.d7sb.adams12.org/files/images/galleries/test-gallery" despite the warning.

Image File names tested: 275952.png

Third Test - Image Field - NO ERROR
Trying to upload a single banner image for the page content type. The banner image field uses the standard image widget. Here are the field settings for this banner image:

File Path = images/banners
File Path Options = none checked
File Name = [file:ffp-name-only-original].[file:ffp-extension-original]
File Name Options = none checked
Number of values = 1
Upload destination = public files
Image File names tested: 275952.png

Fourth Test - File Field - NO ERROR
Trying to upload a single file attachment for the page content type. The file field uses the standard file widget. Here are the field settings for this file field:

File Path = attachments
File Path Options = none checked
File Name = [file:ffp-name-only-original].[file:ffp-extension-original]
File Name Options = none checked
Number of values = unlimited
Upload destination = public files
Image File names tested: Carl Sagan Bio.docx

Fifth Test - File Field - ERROR
Trying to upload a single file attachment for the news content type. The file field uses the standard file widget. Here are the field settings for this file field:

File Path = attachments/news
File Path Options = none checked
File Name = [file:ffp-name-only-original].[file:ffp-extension-original]
File Name Options = none checked
Number of values = unlimited
Upload destination = public files
Image File names tested: Carl Sagan Bio.docx

What Else Could I Report?

This seems really strange to me. I can't seem to find any consistent cause for the error.

This is fixed in dev.

Awesome Deciphered! I can't wait till beta 4 is out. I love this module!