Font change gives an error

Hi there,

I’m trying to change the font of the Album names with no luck.
I went to Table V:Fonts-> Album Titles.
In the “font size” whenever i input any no. I get an undefined error and an x next to the box!
I tried different nos. and still the same problem. (10-20-50).

Please help.

Thanks

https://www.ads-software.com/extend/plugins/wp-photo-album-plus/