I had also a problem with updating history, I found somewhere on this forum the solution already. I had similar problems like you wrote but I solved them.
Now still (and before also) I am missing lot of tracks, so i installed totally new RadioDJ 1.7.1 and I created totally new database. I copied the tables with categories and genres and songs using the PHP Myadmin from the old database to the new. I set all the dates (several columns) fields in all rows to the default date to be sure that all dates and times are OK and also I tried to set subcategory in the table songs to a value of the default subcategory under the category Music, by all rows and I checked that the track type is always 0 = music.
I am able to send you my backup file at the evening to Dropbox, now I am at work and have not the database here.