Sharepoint 2010 error opening .pdf files

When you try to open a PDF document from your standard SharePoint library, as it tries to open it in Acrobat viewer and you encounter the error:

There was an error opening this document. The filename, directory name, or volume label syntax is incorrect.

You can fix it read below:

DON'T

• Change Client Integration
• Change File handling methods

DO

Go to the following Path:

C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\XML

Edit the DOCICON.XML file 

Find this entry

<Mapping Key="pdf" Value="icpdf.png" OpenControl="PdfFile.OpenDocuments"/>

and edit it to 

<Mapping Key="pdf" Value="icpdf.png" OpenControl="SharePoint.OpenDocuments"/>

Hope this fixes your problem