1.
Line 131, column 66: cannot generate system identifier for general entity "pisen"
...220"><div align="left"><a href="index.lp?str=texty&pisen=1-1">01: Papercut</a></div></td>
An entity reference was found in the document, but there is no reference by that name defined. Often this is caused by misspelling the reference name, unencoded ampersands, or by leaving off the trailing semicolon (;). The most common cause of this error is unencoded ampersands in URLs as described by the WDG in "Ampersands in URLs".
Entity references start with an ampersand (&) and end with a semicolon (;). If you want to use a literal ampersand in your document you must encode it as "&" (even inside URLs!). Be careful to end entity references with a semicolon or your entity reference may get interpreted in connection with the following text. Also keep in mind that named entity references are case-sensitive; &Aelig; and æ are different characters.
Note that in most documents, errors related to entity references will trigger up to 5 separate messages from the Validator. Usually these will all disappear when the original problem is fixed.
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2.
Line 131, column 66: general entity "pisen" not defined and no default entity
...220"><div align="left"><a href="index.lp?str=texty&pisen=1-1">01: Papercut</a></div></td>
This is usually a cascading error caused by a an undefined entity reference or use of an unencoded ampersand (&) in an URL or body text. See the previous message for further details.
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3.
Line 131, column 71: reference to entity "pisen" for which no system identifier could be generated
...align="left"><a href="index.lp?str=texty&pisen=1-1">01: Papercut</a></div></td>
This is usually a cascading error caused by a an undefined entity reference or use of an unencoded ampersand (&) in an URL or body text. See the previous message for further details.
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4.
Line 131, column 65: entity was defined here
...="220"><div align="left"><a href="index.lp?str=texty&pisen=1-1">01: Papercut</a></div></td>
aha. no mne to ukazovalo, ze to je validni... jinak je to jasny, misto & pouzij & - pisen neni zadna entita