If I search for an image by text ie Crowd, then no problem however, if I search by any number ie 2014, I get the following response:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, cgiadmin@yourhostingaccount.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

Basic info about your install please. It works with the 1.4.6 RC2 for me (our site for example)

photo.afrikaburn.com

Zenphoto version 1.4.3.2 [10732] (Official build)
Current locale setting: en_US.UTF8
Current gallery theme: zpArdoise
PHP version: 5.3.13
Graphics support: PHP GD library bundled (2.0.34 compatible)
supporting: gif, jpg, jpeg, png, bmp
PHP memory limit: 164M (Note: Your server might allocate less!)
MySql version: 5.5.32
Database name: znp6je7kdoafi
Table prefix: zp
Spam filter: simple
CAPTCHA generator: zenphoto

Please upgrade then please. Also please see:
http://www.zenphoto.org/news/general-contributor-guidelines#reporting-bugs