In MOOS 2007 aspx pages works only on detach from page layout otherwise it's throws error:"The file or folder name contains characters that are not permitted. Please use a different name." so how can i fix it?
Based on your description, I tried to reproduce it, however everything works fine.
Do you use custom master page on the subsite? This may
cause the issue, please check.
Work around: put your custom master page in the master page library of the top site.
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