XML Invalid Tag Error

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I'm getting Warnings in my Google Webmaster profile. Two warnings, both the same:

Line 22 - "Invalid tag value: This XML tag has an invalid value. Please fix it and resubmit."

Line 4696 - "Invalid tag value: This XML tag has an invalid value. Please fix it and resubmit."

Hello,

please check for possible issue as described in Google webmaster tools tells me these warnings (posts #8, #10, #19).

Thanks Oleg. I'll see if it works.