Steps to Reproduce:

When adding a new line item to a quote or order in a non-integrated Sage CRM system you may see the following message after you've clicked save on the line item:
"Validation Error - Please correct the highlighted entries".

But Sage CRM does not show the highlighted entries.

If you try add a "New comment line item" the following message is shown: 
"Pricing Service is not available".

Solution:

Make sure that the custom_sysparam “DontSaveOnPricingError” is set to ‘N’

update custom_sysparams set Parm_Value = 'N' where Parm_Name = 'DontSaveOnPricingError'

Then do an IISReset and test again.