You can attach different filetypes:
Allowed Extension Groups and their Sizes Archives ->
Maximum Upload Size: 2 MB gtar gz tar tgz z zip Documents ->
Maximum Upload Size: 2 MB ai bsz doc dot eps pdf ppt ps wrd xls Executables ->
Maximum Upload Size: 2 MB exe Images ->
Maximum Upload Size: 2 MB gif ief jpe jpeg jpg pbm pgm png pnm ppm ras rgb tif tiff xbm xpm xwd Plain Text ->
Maximum Upload Size: 2 MB asc c cc cpp h hh hpp txt Real Media ->
Maximum Upload Size: 2 MB rm Streams ->
Maximum Upload Size: 2 MB wma @ SiRoCs
Maybe try to change the rendering mode you use to display movies. To do so, go to
Preferences -> Video -> Video rendering 