Upload script file types

Hi there, We are using Zoho Recruit and recently decided to let applicants upload in a videopitch besides their CV on our embedded zoho application form. I did this by creating a (mandatory) upload field called "Videopitch", which seems to work fine: the attachment paperclip shows me a downloadable file. This seems to work fine for .avi and .zip files, but not always for .mov, .mp4, .wmv, .flv and .3gp. The embedded form doesn't give a confirmation message, nor an error message, but just disappears and nothing is uploaded to Zoho (I tested this in Google Chrome with all formats above and only .avi and .zip got accepted by Zoho.) Even stranger: one apllicant did manage to upload a .mov file.. so I am guessing it has something to do with the Zoho upload script being different for different browsers (I assumed that someone who uploads a .mov file is a Mac-user and uploaded it through Safari, but this is only an assumption.) Can you help me out? I could not find anything relevant on the forum. Cheers Alex