no current context is displayed

Hello, I have a question to consult, I use the mouse to select the key frame, I want to get the value of these key frames. I tried it myself, but it kept showing no current context. I wrote that in the first step I get the active item through AEGP_GetActiveItem, in the second step I get the type of the item through AEGP_GetItemType, and in the third step I get the composition through AEGP_GetCompFromItem. In step 4 I get the active layer through AEGP_GetActiveLayer. In the fifth step I get the location attribute stream through AEGP_GetNewLayerStream. In step 6 I get the number of keyframes by AEGP_GetStreamNumKFs, and in step 7 I get each keyframe by iterating >AEGP_GetNewKeyframeValue. But when I run in AE, when I use the mouse to select the keyframe execution code to get the value of the keyframe, it shows an error such as no current context.