I think pgAdmin v1.20.0 was compiled with the same VS chain (2013 as I recall) as the PostgreSQL 9.4 binaries.
These don't work on Windows XP. Probably should be noted somewhere on the site that Windows XP is not supported.
So you have to use a lower version of pgAdmin III . Also you can't use PostgreSQL 9.4 on windows xp either. I ran into the same issue when a PostGIS user complained about the issue (wanting to run PostgreSQL 9.4 and PostGIS on windows xp ) and had to put a notice on the PostGIS windows page to that effect.
Hope that helps,
Regina
My O/S is Windows XP Pro SP3
I just downloaded PgAdmin III v1.20.0 from
http://www.postgresql.org/ftp/pgadmin3/release/v1.20.0/win32/
After installing, I get the following error when trying to run it:
" (null) is not a valid Win32 application. "
To reproduce:
1. download .zip
2. Open .zip and click on pgadmin3msi
3. Follow prompts to install
4. Click on link to PgAdmin III 1.20
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