I'm trying to embed Mathcad 11 blocks in VisSimPE 5.0e but am getting odd system behavior. When inserting a MCad block and editing it, I sometimes get a dialog box that says "Unexpected event. Save your work and restart." Other times I get something about Mathcad variable "out0" not found (when in fact it is there). I even get these errors sometimes when running the sample files that came with VisSim - but not consistently. Also, no matter how many "in#" variables (i.e., in0, in1, etc.) I put in the MCad block, there is only one input attachpoint on the block for the input wires. I am running these products on a Dell 1.8G machine with 512Meg memory running Windows XP Home Edition. Has anyone seen similar issues? I can't tell if these problems are with MathCad 11 or with VisSimPE 5.0e Thanks for your help.