How to solve the problem (Error 1718 *.msp did not pass the digital signature check)when install vs2005 sp1(Team Suite Service Pack 1) in win2003 R2 ?

If you see the above Dialog, you can try the method as following:

First,you should install the service pack :
http://www.microsoft.com/downloads/details.aspx?FamilyId=8EFFE1D9-7224-4586-BE2B-42C9AE5B9071&displaylang=en

then you only should follow step by step :)

1.	Click Start, click Run, type control admintools, and then click OK.
2.	Double-click Local Security Policy.
3.	Click Software Restriction Policies. Note If no software restrictions are listed, right-click Software Restriction Policies, and then click Create New Policy.
4.	Under Object Type, double-click Enforcement.
5.	Click All users except local administrators, and then click OK.
6.	Restart the computer.

Important After you follow the previous steps, local administrators can install the .msi package or the .msp package. After the package is installed, reset the enforcement level by following the previous steps. In step 5, click All users instead of All users except local administrators.