Strange error with EnumRegValue in Windows Server 2003 R2

I am using the following code (I took from somewhere/someone in the NSIS site) to get the ms.net framework v2 folder:

	Exch $R0 ; Set R0 has "v2.0" in it

	Push $R1

	Push $R2

        

        ;This next line prints OK

        DetailPrint "Searching for Microsoft.net $R0"

        

	; set R1 to minor version number of the installed .NET runtime

	EnumRegValue $R1 HKLM \

		"Software\Microsoft\.NetFramework\policy\$R0" 0

	IfErrors getdotnetdir_err



        DetailPrint "Searching for Microsoft.net $R0 build $R1"



	; set R2 to .NET install dir root

	ReadRegStr $R2 HKLM \

		"Software\Microsoft\.NetFramework" "InstallRoot"

	IfErrors getdotnetdir_err



        DetailPrint "Root folder found: $R2"

        DetailPrint "Found folder: $R2$R0.$R1"

        

	; set R0 to the .NET install dir full

	StrCpy $R0 "$R2$R0.$R1"



getdotnetdir_end:

	Pop $R2

	Pop $R1

	Exch $R0 ; return .net install dir full

	Return



getdotnetdir_err:

        DetailPrint "Where were we? $R2$R0.$R1"

	StrCpy $R0 ""

	Goto getdotnetdir_end

The result in Windows Server 2003 R2 is always
"Searching for Microsoft.net v2.0
Where were we? 1v2.0.50727"

So it seems like EnumRegValue returns an error in spite of also returnin the correct key name ("50727").

I changed it to this, in order to get it working:

	

; set R1 to minor version number of the installed .NET runtime

	EnumRegValue $R1 HKLM \

		"Software\Microsoft\.NetFramework\policy\$R0" 0

	StrCmp $R1 "" getdotnetdir_err



        DetailPrint "Searching for Microsoft.net $R0 build $R1"

        ClearErrors

DO you have any idea why this behaviour?

Thanks for your help.
Joel