Here is something what you can try,
1. Download Small Basic 0.9
2. Download FC extension for Small Basic 0.9
3 Change your code to FCFTP.UploadFile("ftp://10.10.115.43/","D:/ads.txt","buffon","mypass")
4. Make sure your program have access to internet
But it looks like your problem is that you have two / after D:
Sorry My Bad English