Need Help With File Uploading Class Allowed Types from Database

[eluser]mm[/eluser]
when i echo $allowed_types, the output is exactly in this format

Code:

doc|avi|mp3|jpg|docx|xls|xlsx|pdf|txt

anyway, just wondering, is there a limit to how many file types we can specify? i have just found out that i can successfully upload files with the first three allowed file extensions. in my case, i can upload .doc, .avi or .mp3, but failed if i upload any files from .jpg to .txt

if there's a limit, may i know where to look for it?