# MapDemo, Dotspatial.Data and GAC

 Wiki Link: [discussion:241488]
 aleberkn Jan 12, 2011 at 5:53 PM I compiled DotSpatial.Data successfully.  I compiled MapDemo successfully as well.   When I try installing mapdemo the system returns a message that DotSpatial.Data needs to be in the GAC.   When I run gacutil /i DotSpatial.Data the system returns an unknown error.    I'm running on Windows 7.  I have the .Net 4 Framework installed.  The gacutil I'm using is from the Microsoft SDK v7.0.   Any ideas what I'm missing?   Thanks, -Alan aleberkn Jan 12, 2011 at 6:37 PM All,   I was able to resolve this.  The mistake I made was in using the wrong gacutil.exe   Initially I used the one under C:\Program Files\Microsoft SDKs\Windows\v7.0A\bin   which failed giving me an unknown error.   When I used the one under C:\Program Files\Microsoft SDKs\Windows\v7.0A\bin\NETFX 4.0 Tools   the dll was successfully added to the gac.   Thanks, Alan