My First Studio

I installed Album app but cannot add a new album (error 500).

This is the error as it appears in the log:

[15-Dec-2016 12:57:33 UTC] PHP Fatal error: Class 'BxBaseModTextFormEntry' not found in /home1/webmfsco/public_html/public_html/modules/boonex/albums/classes/BxAlbumsFormEntry.php on line 16

Can you please advise?

thanks,

Shira