pdfsearch problem?

Just installed the pdfsearch plugin, on a 1.5.1 omeka install. I have no issues extracting text from pdf's. The only way I can successfully search the extracted text is by using the advanced search and then use the specific field with pdf-search selected. Any idea why the normal search is a no go?

Many thanks!

Omeka's normal search uses MySQL's full-text natural language search, which can be temperamental during certain conditions. There are stopwords and minimum word lengths. Apart from that, what is likely happening to you is, for whatever reason, the search engine does not recognize your query as being relevant. There's really no way I can explain exactly why no results are showing, just that the more content you have, the more relevant your queries will become.

I'll continue looking into this matter, but it probably has nothing to do with the PDF Search plugin.

I have installed the PDFsearch and no problem at installation but when I tried to go to config and select the box for Process existing PDF files, I got this error message

The configured PHP path (/usr/bin/php) points to a PHP-CLI binary with an invalid version (5.1.6)

Any idea what is the required version!

The required version is the same for Omeka: 5.2+.