# The "ambiguously referenced component" error + grating presentation problem **URL:** \ **Category:** Support\ **Created:** [January 26, 2011, 9:31pm UTC](https://mworks.discourse.group/t/the-ambiguously-referenced-component-error-grating-presentation-problem/694 "2011-01-26T21:31:24Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [January 26, 2011, 9:31pm UTC](https://mworks.discourse.group/t/the-ambiguously-referenced-component-error-grating-presentation-problem/694/1 "2011-01-26T21:31:24Z")
[From Ha] The “ambiguously referenced component” error has been solved — the reason of the error was that there was a duplicated name both in timer and variable. The following code produces the error since it uses “ignore\_timer” in timer name and variable name: ``` ``` If I change the upper code into the following one, the error disappears (woot! woot!): ``` ``` I, however, still have another issue in presenting gratings. The attached xml has a protocol “RF Mapping” which used to produce 4 differently oriented gratings in 5x5 different positions. If I run the protocol in the nightly build, I don’t see any gratings. (FYI, the two xml files are identical except RF\_Mapping\_02 uses ITC18 and RF\_Mapping\_02\_FE-simple uses Fake Money.) It would be great if you could figure out the grating problem. Thanks a lot! Ha ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [January 26, 2011, 9:31pm UTC](https://mworks.discourse.group/t/the-ambiguously-referenced-component-error-grating-presentation-problem/694/2 "2011-01-26T21:31:24Z")
Attachments: - [RF\_Mapping\_02.xml](https://mworks.discourse.group/uploads/short-url/qKlNf1fKHwPY0FudJM9AShQGq2h.xml) (59.5 KB) - [RF\_Mapping\_02-FE-simple.xml](https://mworks.discourse.group/uploads/short-url/bPv7UDkNvEMN0ousWNU6nhHJ17Z.xml) (55.9 KB) ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [January 26, 2011, 9:32pm UTC](https://mworks.discourse.group/t/the-ambiguously-referenced-component-error-grating-presentation-problem/694/3 "2011-01-26T21:32:04Z")
[From Ha] And plus, the RF\_Mapping\_02.xml does crash MWServer when quitting and when closing the experiment xml file (through MWClient). Thanks! Ha ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [January 26, 2011, 9:44pm UTC](https://mworks.discourse.group/t/the-ambiguously-referenced-component-error-grating-presentation-problem/694/4 "2011-01-26T21:44:03Z")
Hi Ha, > It would be great if you could figure out the grating problem. The drifting grating is a dynamic stimulus. In order for it to display, it has to be playing. You start it playing with a `play_dynamic_stimulus` action and stop it with `stop_dynamic_stimulus`. I’ve attached a simple experiment that demonstrates how to display your grating. In the past, if you queued the drifting grating without playing it, it would draw its first frame, which is presumably why your code used to work. This changed a while ago (over the summer, I think); now, if the grating isn’t playing, it doesn’t display at all. > And plus, the RF\_Mapping\_02.xml does crash MWServer when quitting and when closing the experiment xml file (through MWClient). It crashes on my machine, too, presumably due to a bug in the ITC-18 plugin. I’ll investigate. Thanks, Chris ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [January 26, 2011, 9:44pm UTC](https://mworks.discourse.group/t/the-ambiguously-referenced-component-error-grating-presentation-problem/694/5 "2011-01-26T21:44:03Z")
Attachment: [grating\_demo.xml](https://mworks.discourse.group/uploads/short-url/rZ8X0uPWFU8z7flX3op44ryPLIF.xml) (2.62 KB) ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [January 26, 2011, 10:05pm UTC](https://mworks.discourse.group/t/the-ambiguously-referenced-component-error-grating-presentation-problem/694/6 "2011-01-26T22:05:46Z")
Thanks, Chris! `play_dynamic_stimulus` and `stop_dynamic_stimulus` solved the problem, and now the protocol runs well in the newest version. Thanks a lot! ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [January 31, 2011, 4:39pm UTC](https://mworks.discourse.group/t/the-ambiguously-referenced-component-error-grating-presentation-problem/694/7 "2011-01-31T16:39:37Z")
Hi Ha, I opened a [ticket](http://mworks.lighthouseapp.com/projects/23610/tickets/66) about making the “ambiguously referenced component” message more helpful. Also, I found and fixed the ITC-18 plugin bug that caused MWServer to crash when closing your experiment. The fix will be in tonight’s nightly build. Chris ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [July 19, 2022, 11:51pm UTC](https://mworks.discourse.group/t/the-ambiguously-referenced-component-error-grating-presentation-problem/694/8 "2022-07-19T23:51:06Z")