You are trying to install a new pear package but get an error because pear is configured as stable and the package is beta ?

pear install Spreadsheet_Excel_Writer
Failed to download pear/Spreadsheet_Excel_Writer within preferred state "stable", latest release is version 0.9.3, stability "beta", use "channel://pear.php.net/Spreadsheet_Excel_Writer-0.9.3" to install
install failed

Here some tips to help you :
– force installation with -f

pear install -f Spreadsheet_Excel_Writer-0.9.3

– change pear preferences

pear config-set preferred_state beta
pear install Spreadsheet_Excel_Writer-0.9.3
pear config-set preferred_state stable

or do it directly within the same command

pear -d preferred_state=beta install Spreadsheet_Excel_Writer-0.9.3

– add the shorcut -beta at the end of the package name

pear install Spreadsheet_Excel_Writer-0.9.3-beta