Qt installer framework: installer have problem create License folder during the installation

qtLove

My package.xml

<?xml version="1.0" encoding="UTF-8"?>
<Package>
    <DisplayName>DisplayName</DisplayName>
    <Description>Install the application.</Description>
    <Version>version</Version>
    <ReleaseDate>build_date</ReleaseDate>
    <Name>product name</Name>
    <Licenses>
        <License name="License Agreement" file="license.htm" />
    </Licenses>
    <Default>true</Default>
    <Script>installscript.qs</Script>
    <UserInterfaces>
            <UserInterface>aGUI.ui</UserInterface>
    </UserInterfaces>
</Package>

When I tried to install the program with the installer, all other files and folders are created successfully.
Except the license file,
I got the error message window pop up and said:

Error during installation process. Can not write license file "C:\Program Files\<default installation folder>Licenses\license.html

I have gain admin right with installer.gainAdminRights() and have checked it return true.

I did a bit testing and found if the <default installation folder> is created beforehand then this issue wont happen.
But if the <default installation folder> is created by the installer which is how it suppose to be, the error happen.

I assume that this have something to do with the admin right? but I should have gained it and there is no problem for creating other files and folders.
Have anyone encounter this before?
Thank you for the comment and time

qtLove

I found solution for this later.
By adding

<RequiresAdminRights>true</RequiresAdminRights>

into package.xml
and using

component.addElevatedOperation("License");

in the installscript.qs

so the installer gain admin right for real.

I was using installer.gainAdminRights() in the installscript.qs, but it did not really gain the admin right,
so the error pop up during the installation.

The other thing I can add is that if you have both adding the tag and the installer.gainAdminRights() in the script it will give a not enough memory error during the installation.