2682_E_test_0807-01_L_bidr_betterplan.txt

then copy this file in windows and paste

the file name will be

2682_E_test_0807-01_L_bidr_betterplan-copy.txt

then copy those two files and paste

file name will append copy to the file name

 

this way you will have longer file name

create only 300 to 400 files (each time you paste ,select all files again and paste it will take you less than a minute)

attempt an upload for those files and se if it works

 

i think the problem
has to do with the length of the file names
there seems to be a predefined buffer size for ajax uploader control  
if the sum of bytes of the selected file name is bigger than that buffer size it fails

 

Let me know