Did you disable or flush the cache?
According to you said, 'nothing happened', can you try:
input the 'default' in default field, and input the 'custom_theme' in template,skin and layout field.
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Hi, I just download whole new free theme bluescale and make a sub theme, and edit the header.phtml file and it works.
Since you did not provide more detail about your problems, such as 'nothing happend' or your theme file structure, so I did it whole example for you.
And Magento's structure is based on a fall-back hierarchy, so I GUESS there are something you need check:
- Does 'ultimo' folder has folder named 'default' to supporting your theme?
I just test the custom template on Ultimo theme(Ultimo_v1.3.2), it still working.
All I can say is your configurations for the theme setting seems all good so far.
So I am going to Keep guessing:
did you try remove var folder in the root path ?
did you try check the file permission ?
did you try a clean Magento and install the new custom sub theme. If new clean Magento working with custom sub theme, you may want to disable the extensions one by one to find out which extension causes theme problem.
if all of above nothing work, change the WAMP to XAMPP or keep googling.