could not upload document and could not download existing documents

Dear Sir,

This is the first time that i have facing the problem since i bought last year. The current edocman that i am using is V: 1.9.2. The problem is that we could not upload or download documents any more. Whenever we download it or upload it, it become blank page. Earlier, it functioned normally.
How could we fix this problem?
Regards,
Tony

Hi,
Please try to go to Back-end > Extensions > Plugins and turn off 2 plugins if they are exists
- Edocman Dropbox
- Edocman Amazon S3
Then, you can try to upload document again and let me know the result.
Thanks
Dam