There are numerous UI-related mistakes pertaining to colour (particularly background colour) of texts when using Windows XP, particularly under Windows Classic with a different theme (ex. Rainy Day). The existing UI seems to make assumptions in a lot of places (but not everywhere!) that "the background colour is white", which is simply untrue. It's been like this for years now.
Attached are some screenshots showing the problem (and one screenshot showing where things are done right (the Search tab)). This is 100% reproducible on stock Windows XP Pro SP3 (no weird "themeing" or third-party crap like WindowBlinds installed), and can be reproduced inside of a VM as well, so Piriform should have no problem fixing all this.
ss00.png -- "Status" and "Properties" text is black-on-white; should be black-on-whatever-theme-bg-is
ss01.png -- "Search" tab -- an example where its done correctly. Use this as a reference!
ss02.png -- "Color" has issue
ss03.png -- Self-explanitory (lots to fix here)
ss04.png -- Self-explanitory (lots to fix here)
These shouldn't be time-consuming to fix, despite Microsoft's support for Windows XP ending (I know, I know...). If you need to know what exactly to change in Windows XP to reproduce this (theme-wise) let me know and I can provide exact instructions.