There is very little information available about the film online. It's likely there isn't a readily available cast list.
To find more information, you could try:
* Searching for "The Trigger (2004)" on movie databases like IMDb: Sometimes these databases have entries for even obscure films.
* Searching for the film on the website of the production company (if you know it).
* Searching for the film director's name on online film resources.
Let me know if you have any other information about the film - the director, the production company, or even a specific scene you remember - that might help in identifying the cast.