As mentioned in the linked discussion linked to, Here are the possible solutions:
1)The problem is that the theme folder is called "platformpro" and the Base theme looks for "PlatformPro".
If it is hosted on unix boxes, capitals and small letters are not the same.
Just look at style.css in the Base theme folder, and fix it by writing "platformpro" in these lines:
Template: PlatformPro
/* ======================= */
/* = Get PlatformPro CSS = */
/* ======================= */
/* Get Core CSS */
@import url('../platformpro/core/css/core.css');
/* Get Dynamic CSS */
@import url('..platformpro/core/css/dynamic.css');
/* Get Theme-Parent CSS */
@import url('../platformpro/css/theme.css');
IF #1 DOES NOT WORK, try #2 below.
2)I simply changed the main Platform Pro theme folder name to "PlatformPro"(instead of "platformpro") to P's being in caps and this worked when #1 didn't work.
...These are both temporary fixes and Pagelines need to fix this and many other issues in the next update.