When I started up Morroblivion and started a new game in Morrowind, some of the doors were completely pink and some of the plants and vines were also pink too.
Eloth's Visual Overhaul
I am using Eloth's Visual Overhaul and I haven't gotten past Seyda Neen yet. A lot of plants are pink and there are sometimes pink squares replacing some of the vines. All of the doors in the Seyda Neen Census Office are completely pink or have pink squares replacing what should be part of the door.
You still need to install the
You still need to install the complete install if you use Eloth's Visual Overhaul. (install the complete install first and overwrite it with ELoth's Overhaul).
Pink=Missing
Pink=Missing Textures=Incomplete Install ... specifically with your symptoms , I guess you might be missing part 2 or part 3 of the complete install.
If that doesn't hep then please provide more detail. It helps to have a list of all files that you have downloaded\installed, it helps to know exactly which doors are pink ( Imperial, Hlaalu, Redoran, Velothi, Telvanni .. etc.) and it also helps to know if you are using any texture\mesh replacers like Eloth's Visual Overhaul.