& (ampersand) HTML code in URL request -- causes 500 server error -- browser problem?

Observe the following apache access log entry:

Note the 5 character HTML coded ampersand (&) as part of the URL, instead of the single "&" character. This causes G2 to issue 500 server error and the user is getting no pictures. I presume this is a fault of the browser, but, I wonder if there's anyway to accept this URL request and handle it properly. A simple regex substitution (s/\&/\&/g) before processing the request would do the job.

Often, when I see this, it's the result of poorly implemented spammer site suckers, or other malware (my gallery is excluded in robots.txt), however, I do also see it from what looks like legitimate web traffic -- arrived into a different part of the site though a web search and clicked through to the gallery photos embedded there. Thus, I'd sincerely appreciate any help.

Gallery version = 2.2.4 core 1.2.0.6
PHP version = 5.1.6 apache2handler
Webserver = Apache
Database = mysql 5.0.22, lock.system=flock
Toolkits = ArchiveUpload, Exif, NetPBM, ImageMagick
Acceleration = none/2700, none/2700
Operating system = 2.6.18-53.1.19.el5.centos.plus #1 SMP Sat May 10 11:10:58 EDT 2008 i686
Default theme = carbon
gettext = enabled
Locale = en_US
Rows in GalleryAccessMap table = 29
Rows in GalleryAccessSubscriberMap table = 1262
Rows in GalleryUser table = 4
Rows in GalleryItem table = 1261
Rows in GalleryAlbumItem table = 63
Rows in GalleryCacheMap table = 0