Delayed Write Failed problem

Hello.
Windows 2008R2 std (clean installation with all updates from MS WU installed), 16 GB RAM, size of disk is 12 GB, Intel core i7-3770.

Lots of errors in System log (~every 2 minutes) begin when high processor load (just one core of eight loaded, hyperthreading enabled) while processing database file (custom accounting application) with text info.
The same errors appear not so often (twice a day) under low load.
That all results in database corruption

Ntfs eventid 57 category (2) The system failed to flush data to the transaction log. Corruption may occur.
Ntfs eventid 141
exfat eventid 141 {Delayed Write Failed} Windows was unable to save all the data for the file ... the data has been lost. This error may be caused if the device has been removed or the media is write-protected.
exfat eventid 50 {Delayed Write Failed} Windows was unable to save all the data for the file ... The data has been lost. This error may be caused by a failure of your computer hardware or network connection. Please try to save this file elsewhere.

Is it normal?

Not quite normal I suppose. Are you using an associated image file with this RAM Disk and periodic save?

Yes, I do. It loads on boot and saves once per 30 minutes.
Note that the errors are about the files on RAM disk but not on the Hard drive which keeps the image file.

Symptoms like you described sometimes happen when using an image file with a RAM Disk and it's saved periodically. When this happens, the disk is temporarily locked out from writing on it and many apps may fail if they encounter this situation.

I would recommend trying not to use the image file. You can backup the drive contents with an archiver or a tool like Robocopy/Unison. Alternatively try a different file system, e.g. FAT32 to see if this helps.