Refer to this article.
Please refer to this thread and report your problem.
Read the manual describing automatic correction.
The database files are located in "\System\DATA" folder, which is hidden and inaccessible. However, you can see these files by entering "D:\System\DATA" directly to the address bar in the Explorer and pressing [Enter] key. Needless to say, the MTP users must use UMS trick to open this folder.
Yes.
Yes.
No. iriver H10 [1GB; color] seems to use a totally different database specification. I am developing a new tool that supports iriver H10Jr and U10.
I'm not sure because I've never used DRM'ed WMA files. I suppose that EasyH10 will recognize DRM'ed WMA files located in the H10 player only if you transferred them by using iriver plus or Windows Media Player.
Yes. EasyH10 [CUI] can be compiled and work on Linux and MacOS X successfully.